Space purifying device

Abstract

A space purifying device (1) comprises: a first supply bath (10) which stores a first aqueous solution (L1) that contains chloride ions and in which the chloride ions contained in the first aqueous solution (L1) are passed through a negative ion exchange membrane (41) via first diaphragm electrolysis such that the chloride ions are supplied to a third aqueous solution (L3); a second supply bath (20) which stores a second aqueous solution (L2) that contains at least one type of metal ion and in which the metal ions contained in the second aqueous solution (L2) are passed through a positive ion exchange membrane (42) via second diaphragm electrolysis such that the metal ions are supplied to the third aqueous solution (L3); and an electrolytic bath (30) which stores the third aqueous solution (L3) containing the chloride ions and in which diaphragm-less electrolysis is performed on the third aqueous solution (L3) to generate hypochlorous acid. The space purifying device (1) having the above configuration performs a purification operation in which air introduced from an external space (R) flows through the electrolytic bath (30) and is released to the external space (R) along with hypochlorous acid.

Description

Space Purification Device

[0001] The present disclosure relates to a space purification device.

[0002] Patent Document 1 discloses an air purifying device that uses hypochlorous acid generated by electrolyzing a sodium chloride aqueous solution to remove bacteria, fungi, viruses, odors, and the like contained in the air.

[0003] Japanese Patent Application Laid-Open No. 2019-174032

[0004] When a conventional space purification device is downsized, the tank that stores the aqueous solution used for electrolysis also becomes smaller. This downsizing of the tank reduces the amount of aqueous solution that can be stored compared to conventional space purification devices. Therefore, when electrolysis is repeatedly performed in a downsized space purification device, the chloride ion concentration in the aqueous solution tends to decrease, resulting in an unstable amount of hypochlorous acid generated.

[0005] The present disclosure provides a space purification device that can stably generate a desired amount of hypochlorous acid gas over a long period of time without externally supplying an aqueous solution containing chloride ions.

[0006] The space purification device according to the present disclosure includes a first supply tank for storing a first aqueous solution containing chloride ions and for supplying the chloride ions contained in the first aqueous solution to a third aqueous solution by passing them through an anion exchange membrane through a first diaphragm-equipped electrolysis, a second supply tank for storing a second aqueous solution containing at least one metal ion selected from the group consisting of sodium ions, lithium ions, and potassium ions and for supplying the metal ions contained in the second aqueous solution to a third aqueous solution by passing them through a cation exchange membrane through a second diaphragm-equipped electrolysis, and an electrolytic cell for storing a third aqueous solution containing chloride ions and for producing hypochlorous acid by electrolyzing the third aqueous solution without a diaphragm. The space purification device according to the present disclosure having the above configuration performs a purification operation in which air introduced from an external space flows through the electrolytic cell and is released into the external space together with hypochlorous acid.

[0007] The present disclosure provides a space purification device that can stably generate a desired amount of hypochlorous acid gas for a long period of time without supplying an aqueous solution containing chloride ions from the outside.

[0008] FIG. 1 is a front cross-sectional view showing a space purification device according to an embodiment. FIG. 2 is a partial cross-sectional plan view taken along line II-II in FIG. 1 , showing a first example of each electrolysis unit included in the space purification device. FIG. 3 is a partial cross-sectional plan view taken along line II-II in FIG. 1 , showing a second example of each electrolysis unit included in the space purification device. FIG. 4 is a list of chemical reactions occurring in the first aqueous solution stored in the first supply tank of the first diaphragm electrolysis unit and in the third aqueous solution stored in the electrolysis tank. FIG. 5 is a list of chemical reactions occurring in the first aqueous solution stored in the first supply tank of the second diaphragm electrolysis unit and in the second aqueous solution stored in the second supply tank. FIG. 6 is a list of chemical reactions occurring in the second aqueous solution stored in the second supply tank of the second diaphragm electrolysis unit and in the third aqueous solution stored in the electrolysis tank. Fig. 7 is a list of reaction formulas occurring in the third aqueous solution stored in the electrolytic cell of the membraneless electrolysis unit. Fig. 8 is a block diagram showing a current control unit according to an embodiment.

[0009] Specific embodiments of the present disclosure will be described in detail below with reference to the drawings.

[0010] The xyz coordinates shown in the drawings are for the convenience of explaining the positional relationships of the components. Unless otherwise specified, the positive direction of the z axis is vertically upward. The xy plane is a horizontal plane, and is common to all drawings.

[0011] 1 is a front cross-sectional view showing a space purification device 1 according to an embodiment. The space purification device 1 generates and volatilizes hypochlorous acid by electrolyzing a third aqueous solution L3 containing chloride ions in an electrolytic cell 30 (described later). The space purification device 1 removes bacteria, fungi, viruses, odors, and the like contained in the air in the external space of the space purification device 1 by discharging the volatilized hypochlorous acid into the external space of the housing C that constitutes the space purification device 1.

[0012] The space purification device 1 is installed indoors. The installation location of the space purification device 1 is preferably a location where air flow can occur. More specifically, the installation location of the space purification device 1 is indoors, and more specifically, includes, for example, inside an air conditioner, which is an air conditioner, around an electric fan, around a circulator, around a ceiling fan, inside a humidifier, inside an air purifier, and on a desk.

[0013] As shown in FIG. 1, the spatial purification device 1 includes a housing C, a first supply tank 10 , a second supply tank 20 , an electrolytic tank 30 , an anion exchange membrane 41 , a cation exchange membrane 42 , and a current control unit 50 .

[0014] The housing C houses the first supply tank 10, the second supply tank 20, the electrolytic tank 30, the anion exchange membrane 41, the cation exchange membrane 42, and the current control unit 50. That is, the space purification device 1 may be an integrated unit formed by the housing C. The shape of the housing C can be changed appropriately depending on the location where the space purification device 1 is installed, and may be, for example, a rectangular parallelepiped or cylindrical shape. The space purification device 1 is small enough to be stored inside an air conditioner, for example, and when the housing C is rectangular, it is approximately 10 cm x 7 cm x 4 cm.

[0015] Assuming continuous use for eight hours a day for one year, the volumes of the first supply tank 10, the second supply tank 20, and the electrolytic tank 30 are preferably set, for example, such that the volume of the first supply tank 10 is at least about 12 times the volume of the electrolytic tank 30. Furthermore, the volume of the second supply tank 20 is preferably at least about 6 times the volume of the electrolytic tank 30. By setting these volume ratios, the first supply tank 10 can store the first aqueous solution L1 containing a sufficient amount of chloride ions necessary to supply to the third aqueous solution L3 of the electrolytic tank 30. Furthermore, the second supply tank 20 can store the second aqueous solution L2 containing a sufficient amount of metal ions (metal ions selected from the group consisting of sodium ions, lithium ions, and potassium ions, as described below) necessary to supply to the third aqueous solution L3 of the electrolytic tank 30. Therefore, a necessary amount of chloride ions can be stably supplied from the first aqueous solution L1 stored in the first supply tank 10 to the third aqueous solution L3 stored in the electrolytic tank 30. Similarly, a necessary amount of metal ions can be stably supplied from the second aqueous solution L2 stored in the second supply tank 20 to the third aqueous solution L3 stored in the electrolytic bath 30. The amount of the third aqueous solution L3 stored in the electrolytic bath 30 is, for example, about 2 mL to 10 mL.

[0016] The first supply tank 10, the second supply tank 20, and the electrolytic tank 30 are arranged in this order from the negative side of the x-axis in a front view: second supply tank 20, electrolytic tank 30, and first supply tank 10. An anion exchange membrane 41 is arranged between the first supply tank 10 and the electrolytic tank 30. A cation exchange membrane 42 is arranged between the second supply tank 20 and the electrolytic tank 30. For example, if the surfaces where the first supply tank 10 and the electrolytic tank 30 face each other are formed by a frame-shaped member, the anion exchange membrane 41 may be arranged so as to be fitted into the frame-shaped member. Similarly, if the surfaces where the second supply tank 20 and the electrolytic tank 30 face each other are formed by a frame-shaped member, the cation exchange membrane 42 may be arranged so as to be fitted into the frame-shaped member. The current control unit 50 is arranged at any position within the housing C.

[0017] The first supply tank 10 is a tank for storing a first aqueous solution L1 containing chloride ions and supplying the chloride ions contained in the first aqueous solution L1 to the third aqueous solution L3. In FIG. 1, the first aqueous solution L1 is shown stored in the first supply tank 10.

[0018] To ensure safety in the event of leakage, the solute of the first aqueous solution L1 is preferably a substance classified under the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) as being as safe as sodium chloride. Specifically, the first aqueous solution L1 is a metal chloride aqueous solution containing metal ions and chloride ions. When the first aqueous solution L1 is subjected to the first membrane electrolysis described below, the metal ions contained in the first aqueous solution L1 react with the hydroxide ions generated by the first membrane electrolysis to form a metal hydroxide precipitate. Preferably, the first aqueous solution L1 is a high-concentration magnesium chloride aqueous solution or a saturated magnesium chloride aqueous solution.

[0019] When a magnesium chloride aqueous solution is used as the first aqueous solution L1, the mass percentage concentration of the magnesium chloride aqueous solution is, for example, 1% to 35%. As an example, when the first aqueous solution L1 is a magnesium chloride aqueous solution, by performing the first diaphragm electrolysis described below, magnesium ions contained in the magnesium chloride aqueous solution react with hydroxide ions generated by the first diaphragm electrolysis to form a precipitate of magnesium hydroxide. Note that the "precipitate" of magnesium hydroxide includes hard sand, colloid, slurry, and gel forms, as well as a cloudy aqueous solution.

[0020] The first supply tank 10 includes a first supply tank-side cathode 11 , a first supply tank-side internal space 12 , and a first outlet 13 .

[0021] The first supply tank side cathode 11 is inserted from the outside of the first supply tank 10 toward the inside. The first supply tank side cathode 11 has a plate-like shape. Plate-like shapes include a rectangular shape and a rectangular shape. The first supply tank side cathode 11 is paired with an electrolytic cell side anode 31 (described later) and the first supply tank side cathode 11, and is used in first membrane-with-diaphragm electrolysis via an anion exchange membrane 41. Details of the first membrane-with-diaphragm electrolysis will be described later with reference to FIG. 2 . Chloride ions are supplied from the first aqueous solution L1 to the third aqueous solution L3 by the first membrane-with-diaphragm electrolysis of the first aqueous solution L1 performed using the pair of the first supply tank side cathode 11 and the electrolytic cell side anode 31.

[0022] An insoluble electrode may be used as the first supply tank side cathode 11. More specifically, for example, a platinum-iridium-titanium electrode, a platinum electrode, a ruthenium-titanium electrode, or an iridium-titanium oxide electrode may be used.

[0023] The first supply tank-side internal space 12 is an upper space (space on the positive z-axis side) formed above the liquid level S1 of the first aqueous solution L1 when the first aqueous solution L1 is stored in the first supply tank 10. In other words, the first aqueous solution L1 is not stored up to the internal upper surface of the first supply tank 10 (xy plane on the positive z-axis side), and the first supply tank 10 has the first supply tank-side internal space 12.

[0024] The first outlet 13 is an opening for discharging hydrogen gas generated by the first diaphragm electrolysis of the first aqueous solution L1 to the external space R of the casing C. The first outlet 13 is, for example, a check valve. When a check valve is used as the first outlet 13, hydrogen gas inside the first supply tank 10 is discharged to the external space R, but the inflow of gases such as air from the external space R can be suppressed. When the diaphragm electrolysis of the first aqueous solution L1 is repeated, hydrogen gas accumulates in the first supply tank-side internal space 12, and the internal pressure of the first supply tank 10 increases. This internal pressure opens the check valve of the first outlet 13, and the hydrogen gas is discharged to the external space R of the first supply tank 10.

[0025] The second supply tank 20 is a tank for storing the second aqueous solution L2 containing metal ions and for supplying the metal ions contained in the second aqueous solution L2 to the third aqueous solution L3. In FIG. 1, the second supply tank 20 shows a state in which the second aqueous solution L2 is stored.

[0026] To ensure safety in the event of leakage, the solute of the second aqueous solution L2 is preferably a substance classified under the GHS as being as safe as sodium chloride. Specifically, the second aqueous solution L2 is a metal compound aqueous solution containing at least one metal ion selected from the group consisting of sodium ions, lithium ions, and potassium ions. That is, the metal ions contained in the second aqueous solution L2 may be one or more types selected from the group consisting of sodium ions, lithium ions, and potassium ions, or a combination of two or three types.

[0027] More specifically, the second aqueous solution L2 is preferably a solution of disodium hydrogen phosphate (Na ２ HPO ４ ) aqueous solution, sodium bicarbonate (NaHCO ３ ) aqueous solution, lithium carbonate (LiCO ３ ) aqueous solution, potassium carbonate (K ２ CO ３ ) aqueous solutions. That is, the second aqueous solution L2 may be one or more aqueous solutions selected from the group consisting of disodium hydrogen phosphate aqueous solution, sodium bicarbonate aqueous solution, lithium carbonate aqueous solution, and potassium carbonate aqueous solution, or a combination of two, three, or four aqueous solutions. The disodium hydrogen phosphate aqueous solution, sodium bicarbonate aqueous solution, lithium carbonate aqueous solution, and potassium carbonate aqueous solution may be saturated disodium hydrogen phosphate aqueous solution, saturated sodium bicarbonate aqueous solution, saturated lithium carbonate aqueous solution, and saturated potassium carbonate aqueous solution. Note that "saturated" in this specification also includes cases where the solute does not dissolve in water and precipitates. The specific amount of solute dissolved in each aqueous solution is as shown below. Note that the amount of solute dissolved in each aqueous solution shown below includes both the concentration in the initial state when use of the space purification device 1 begins and the concentration in the second aqueous solution L2 when the concentration decreases as the space purification device 1 is used.

[0028] When a disodium hydrogen phosphate aqueous solution is used as the second aqueous solution L2, the amount of disodium hydrogen phosphate aqueous solution dissolved is, for example, 1 g to 8 g per 100 g of water.

[0029] When a sodium bicarbonate aqueous solution is used as the second aqueous solution L2, the amount of the sodium bicarbonate aqueous solution dissolved is, for example, 1 to 10 g per 100 g of water.

[0030] When a lithium carbonate aqueous solution is used as the second aqueous solution L2, the amount of the lithium carbonate aqueous solution dissolved is, for example, 1 to 2 g per 100 g of water.

[0031] When an aqueous potassium carbonate solution is used as the second aqueous solution L2, the amount of the aqueous potassium carbonate solution dissolved in 100 g of water is, for example, 1 to 112 g.

[0032] When a combination of two aqueous solutions selected from the group consisting of a disodium hydrogen phosphate aqueous solution, a sodium hydrogen carbonate aqueous solution, a lithium carbonate aqueous solution, and a potassium carbonate aqueous solution is used as the second aqueous solution L2, the amount of the mixed solution dissolved in 100 g of water is, for example, 1 to 122 g.

[0033] When a combination of three aqueous solutions selected from the group consisting of a disodium hydrogen phosphate aqueous solution, a sodium hydrogen carbonate aqueous solution, a lithium carbonate aqueous solution, and a potassium carbonate aqueous solution is used as the second aqueous solution L2, the amount of the mixed solution dissolved is, for example, 1 to 130 g per 100 g of water.

[0034] When a mixed solution of a combination of four aqueous solutions, namely, disodium hydrogen phosphate aqueous solution, sodium hydrogen carbonate aqueous solution, lithium carbonate aqueous solution, and potassium carbonate aqueous solution, is used as the second aqueous solution L2, the amount of the mixed solution dissolved in 100 g of water is, for example, 1 to 132 g.

[0035] The second supply tank 20 includes a second supply tank-side anode 21 , a second supply tank-side internal space 22 , and a second outlet 23 .

[0036] The second supply tank side anode 21 is inserted from the outside of the second supply tank 20 toward the inside. The second supply tank side anode 21 has a plate-like shape. Plate-like shapes include a rectangular shape and a rectangular shape. The second supply tank side anode 21 is paired with an electrolytic cell side cathode 32 (described later) and the second supply tank side anode 21, and is used for second membrane-with-diaphragm electrolysis via a cation exchange membrane 42. Details of the second membrane-with-diaphragm electrolysis will be described later with reference to FIG. 2 . Metal ions are supplied from the second aqueous solution L2 to the third aqueous solution L3 by the second membrane-with-diaphragm electrolysis of the second aqueous solution L2 performed using the pair of the second supply tank side anode 21 and the electrolytic cell side cathode 32.

[0037] An insoluble electrode may be used as the second supply tank-side anode 21. More specifically, for example, a platinum-iridium-titanium electrode, a platinum electrode, a ruthenium-titanium electrode, or an iridium-titanium oxide electrode may be used.

[0038] The second supply tank-side internal space 22 is an upper space (space on the positive z-axis side) formed above the liquid level S2 of the second aqueous solution L2 when the second aqueous solution L2 is stored in the second supply tank 20. In other words, the second aqueous solution L2 is not stored up to the internal upper surface of the second supply tank 20 (xy plane on the positive z-axis side), and the second supply tank 20 has the second supply tank-side internal space 22.

[0039] The second outlet 23 is an opening for discharging oxygen generated by the second diaphragm electrolysis of the second aqueous solution L2 to the external space R of the casing C. The second outlet 23 is, for example, a check valve. When a check valve is used as the second outlet 23, oxygen inside the second supply tank 20 is discharged to the external space R, but the inflow of gases such as air from the external space R can be suppressed. When the diaphragm electrolysis of the second aqueous solution L2 is repeated, oxygen accumulates in the second supply tank-side internal space 22, and the internal pressure of the second supply tank 20 increases. This internal pressure opens the check valve of the second outlet 23, and oxygen is discharged to the external space R of the second supply tank 20.

[0040] The electrolytic bath 30 is a bath for storing a third aqueous solution L3 containing chloride ions. The electrolytic bath 30 has, for example, a box-like shape. FIG. 1 shows a state in which the third aqueous solution L3 is stored in the electrolytic bath 30. The third aqueous solution L3 is, for example, an aqueous solution in which an electrically conductive electrolyte is dissolved, and specifically, a dilute chloride aqueous solution having a predetermined chloride ion concentration. More specifically, the third aqueous solution L3 is, for example, a dilute sodium chloride aqueous solution or a dilute potassium chloride aqueous solution.

[0041] The "predetermined chloride ion concentration" of the third aqueous solution L3 includes both a chloride ion concentration having a predetermined numerical range and a chloride ion concentration having a predetermined numerical value. More specifically, the chloride ion concentration of the third aqueous solution L3 may be, for example, 1 g / L to 50 g / L, or may be 10 g / L. In other words, the mass percent concentration of the dilute sodium chloride aqueous solution or dilute potassium chloride aqueous solution may be, for example, 0.1% to 5%, or may be 5%. By setting the predetermined chloride ion concentration to this numerical range or numerical value, it is possible to generate hypochlorous acid necessary for space purification while simultaneously suppressing the generation of chlorine, which may be generated.

[0042] The electrolytic cell 30 includes an electrolytic cell-side anode 31, an electrolytic cell-side cathode 32, an air supply unit 33, an air duct 34, an electrolytic cell-side internal space 35, a water recovery unit 36, and an outlet 37. The electrolytic cell 30 may further include a water level detection unit 38.

[0043] The electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32 are a pair of electrodes used for electrolyzing the third aqueous solution L3. The electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32 are each inserted from the outside to the inside of the electrolytic cell 30. The electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32 each have a plate-like shape. Examples of plate-like shapes include rectangular and oblong shapes.

[0044] Insoluble electrodes may be used as the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32. More specifically, for example, a platinum-iridium-titanium electrode, a platinum electrode, a ruthenium-titanium electrode, an iridium-titanium oxide electrode, a titanium electrode, a titanium oxide electrode, a nickel electrode, a nickel oxide electrode, or a stainless steel electrode may be used.

[0045] No diaphragm such as an ion exchange membrane is provided between the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32. That is, the electrolysis of the third aqueous solution L3 performed using the pair of electrolytic cell-side anode 31 and electrolytic cell-side cathode 32 is diaphragm-less electrolysis. Hypochlorous acid, which is used for space purification of the external space R, is produced by the diaphragm-less electrolysis of the third aqueous solution L3 performed using the pair of electrolytic cell-side anode 31 and electrolytic cell-side cathode 32.

[0046] The yz plane on the negative side of the x-axis of the electrolytic cell-side anode 31 and the yz plane on the positive side of the x-axis of the electrolytic cell-side cathode 32 are arranged opposite to each other. This arrangement allows a uniform electric field to be generated between the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32. Because electrolysis is uniformly generated, the current between the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32 is also uniformly distributed. Therefore, deterioration of the catalyst layer on the surface of each electrode (the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32) occurs uniformly, and uneven deterioration of the catalyst layer on the surface of each electrode due to an uneven electric field can be suppressed even when electrolysis is performed repeatedly. Therefore, the space purification device 1 in this embodiment can suppress a decrease in the electrolysis efficiency of diaphragm-less electrolysis.

[0047] The air supply unit 33 is a blower or an opening that introduces air from the external space R into the electrolytic cell 30. When the air supply unit 33 is an opening, it is preferably disposed in any position that allows air to circulate through the opening, such as a circulator, a fan, a ceiling fan, or other blower disposed inside the air conditioner or outside the space purification device 1.

[0048] The air duct 34 is a tubular member that connects the air supply unit 33 and the electrolytic cell 30. One end of the air supply unit 33 is arranged on the external space R side, and the other end is connected to the air duct 34 side. One end of the air duct 34 is connected to the air supply unit 33 side, and the other end is connected to the electrolytic cell 30 side. The end of the air duct 34 arranged on the electrolytic cell 30 side is connected to the electrolytic cell 30 so as to be located below the liquid level S3 of the third aqueous solution L3 stored in the electrolytic cell 30 (negative side of the z-axis).

[0049] The air supply unit 33 supplies air from the external space R into the third aqueous solution L3 stored in the electrolytic cell 30 via the air blower duct 34. The air introduced into the third aqueous solution L3 via the air supply unit 33 and the air blower duct 34 is released as bubbles B.

[0050] The electrolytic cell-side internal space 35 is an upper space (space on the positive z-axis side) formed above the liquid level S3 of the third aqueous solution L3 when the third aqueous solution L3 is stored in the electrolytic cell 30. In other words, the third aqueous solution L3 is not stored up to the internal upper surface of the electrolytic cell 30 (xy plane on the positive z-axis side), and the electrolytic cell 30 has the electrolytic cell-side internal space 35.

[0051] The water recovery unit 36 ​​is a component that flows through the interior of the space purification device 1 and recovers moisture contained in the air released from the electrolytic cell 30 to the external space R as a liquid and returns it to the electrolytic cell 30. The water recovery unit 36 ​​is, for example, a Peltier element that can cool the moisture contained in the air and condense it into water droplets. In order to recover moisture contained in the air flowing through the interior of the space purification device 1, the water recovery unit 36 ​​may be disposed at the discharge port 37 through which the air passes when it is released to the external space R. When the water recovery unit 36 ​​is disposed at the discharge port 37, moisture contained in the air that has flowed through the interior of the space purification device 1 can be efficiently recovered. The water recovery unit 36 ​​may be disposed at any position in the electrolytic cell-side internal space 35.

[0052] The outlet 37 is an opening for releasing mixed air M, which is a mixture of air flowing in from the air supply unit 33 and hypochlorous acid generated from the third aqueous solution L3 by diaphragm-less electrolysis, into the external space R of the casing C. In FIG. 1 , the outlet 37 is provided on the top surface (xy plane on the positive z-axis side) of the electrolytic cell 30 as an example, but it may be located above the liquid level S3 of the third aqueous solution L3. The shape of the outlet 37 is tubular, including, for example, a cylindrical or rectangular tubular shape. When the top surface (the surface on the positive z-axis side) of the electrolytic cell 30 is close to the ceiling surface of the casing C, the outlet 37 may be a hole-like opening provided in a part of the top surface of the electrolytic cell 30. Alternatively, the outlet 37 and the top surface (the surface on the positive z-axis side) of the casing C may be integrally formed.

[0053] The outlet 37 may be provided with an openable or detachable lid (not shown). The lid may be configured to be closed when the space purification device 1 is transported, moved, or installed, and to be opened or detached when the space purification device 1 is used.

[0054] The space purification device 1 according to this embodiment performs a purification operation in which air introduced from the external space R flows through the electrolytic cell 30 and is released into the external space together with hypochlorous acid. The air flow path A indicated by the outline arrow in Fig. 1 is a series of paths along which air supplied from the external space R to the space purification device 1 flows through the electrolytic cell 30 and is released into the external space R as mixed air M containing hypochlorous acid. That is, the air flow path A indicates the flow of air from the external space R, the air supply unit 33, the air duct 34, the third aqueous solution L3 stored in the electrolytic cell 30, the electrolytic cell-side internal space 35, the water recovery unit 36, the discharge port 37, and to the external space R.

[0055] 1 , in the air flow path A, air is released as bubbles B from the external space R via the air supply unit 33 and the air blower duct 34 into the third aqueous solution L3 stored in the electrolytic cell 30. In other words, the bubbles B are generated by bubbling the third aqueous solution L3 with the air introduced from the external space R. The bubbles B are mixed with hypochlorous acid generated by the diaphragm-less electrolysis of the third aqueous solution L3 to form mixed air M.

[0056] Here, the hypochlorous acid generated by the membrane-less electrolysis of the third aqueous solution L3 includes both hypochlorous acid dissolved in the third aqueous solution L3 and hypochlorous acid gas that has volatilized and gasified into the electrolytic cell-side internal space 35. The hypochlorous acid dissolved in the third aqueous solution L3 is mixed with the bubbles B to form mixed air M. The mixed air M is discharged from the discharge port 37 to the external space R via the water recovery unit 36. The hypochlorous acid gas that has volatilized and gasified into the electrolytic cell-side internal space 35 is mixed with the bubbles B mixed with hypochlorous acid to form mixed air M, and the mixed air M is discharged from the discharge port 37 to the external space R via the water recovery unit 36.

[0057] When bubbles B are generated in the third aqueous solution L3 by bubbling, the bubbles B rise toward the liquid surface S3 due to buoyancy, resulting in gas-liquid contact between the hypochlorous acid and the bubbles B, allowing the hypochlorous acid to be incorporated into the bubbles B. In other words, compared to gas-liquid contact between air and the liquid surface S3 of the third aqueous solution L3, gas-liquid contact resulting from the generation of bubbles B in the third aqueous solution L3 by bubbling allows more hypochlorous acid to be incorporated into the bubbles B. Therefore, the mixed air M incorporating more hypochlorous acid can be released into the external space R. The mixed air M contains moisture that has evaporated from the third aqueous solution L3, but this moisture contained in the mixed air M is recovered by the water recovery unit 36 ​​and returned to the third aqueous solution L3 as water droplets.

[0058] The space purification device 1 purifies the external space R by using the mixed air M containing hypochlorous acid that is released from the outlet 37 into the external space R. That is, the space purification device 1 removes bacteria, fungi, viruses, odors, and the like contained in the air of the external space R by using the mixed air M containing hypochlorous acid.

[0059] The electrolytic cell 30 may further include a water level detector 38. The water level detector 38 detects the position of the liquid level S3 of the third aqueous solution L3. The water level detector 38 is, for example, a water level sensor. The water level detector 38 is disposed above (on the positive z-axis side) the upper ends (on the positive z-axis side) of at least the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32.

[0060] When the space purification device 1 includes a water level detection unit 38, the water recovery unit 36 ​​supplies water to the electrolytic cell 30 based on the position of the liquid level S3 detected by the water level detection unit 38. More specifically, the water recovery unit 36 ​​supplies water to the electrolytic cell 30 so that the water level does not fall below the upper ends (portions on the positive side of the z-axis) of the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32. Furthermore, the water recovery unit 36 ​​supplies water to the electrolytic cell 30 so that the water level does not fall below the upper end (portion on the positive side of the z-axis) of the air blower duct 34 connected to the electrolytic cell 30.

[0061] When the space purification device 1 is equipped with the water recovery unit 36 ​​and the water level detection unit 38, the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32 can be maintained immersed in the third aqueous solution L3. This prevents the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32 from being exposed to air due to a decrease in the third aqueous solution L3, thereby maintaining the electrolysis efficiency of the diaphragm-less electrolysis. The first supply tank 10 and the second supply tank 20 may also be equipped with a water recovery unit and a water level detection unit similar to those of the electrolytic cell 30.

[0062] The anion exchange membrane 41 is provided to connect the first supply tank 10 and the electrolytic tank 30, and is a membranous member that allows anions to pass therethrough based on a voltage applied between the first supply tank 10 and the electrolytic tank 30. More specifically, when a voltage is applied between the first supply tank side cathode 11 and the electrolytic tank side anode 31, first membrane-with-diaphragm electrolysis is carried out via the anion exchange membrane 41. By the first membrane-with-diaphragm electrolysis using the first supply tank side cathode 11 and the electrolytic tank side anode 31, chloride ions contained in the first aqueous solution L1 permeate the anion exchange membrane 41 and are supplied to the third aqueous solution L3 (indicated by a thick black arrow in the negative direction of the x-axis).

[0063] The anion exchange membrane 41 in this embodiment is not a type of anion exchange membrane through which anions permeate due to osmotic pressure without using electricity. Furthermore, magnesium ions, which are cations, do not permeate the anion exchange membrane 41. More specifically, when chloride ions contained in the first aqueous solution L1 permeate the anion exchange membrane 41 and are supplied to the third aqueous solution L3 by first membrane electrolysis using the first supply tank-side cathode 11 and the electrolytic cell-side anode 31, magnesium ions, which are cations, do not permeate the anion exchange membrane 41. The anion exchange membrane 41 is, for example, a hydrocarbon-based anion exchange membrane, and includes membranes that have monovalent anion-selective permeability, alkali resistance, and high-temperature resistance.

[0064] The plane of the first supply tank side cathode 11 on the anion exchange membrane 41 side (yz plane on the negative side of the x-axis) and the plane of the electrolytic cell side anode 31 on the anion exchange membrane 41 side (yz plane on the positive side of the x-axis) are arranged opposite each other with the anion exchange membrane 41 interposed therebetween. That is, the first supply tank side cathode 11, the anion exchange membrane 41, and the electrolytic cell side anode 31 are arranged at a predetermined distance along one direction (x-axis direction) in which chloride ions contained in the first aqueous solution L1 permeate the anion exchange membrane 41 and are supplied to the third aqueous solution L3. This arrangement allows a uniform electric field to be generated between the first supply tank side cathode 11 and the electrolytic cell side anode 31. Since electrolysis is generated uniformly, the current between the first supply tank side cathode 11 and the electrolytic cell side anode 31 is also uniformly distributed. Therefore, deterioration of the catalytic layer on the surface of each electrode (first supply tank-side cathode 11 and electrolytic tank-side anode 31) occurs uniformly, and therefore, even when electrolysis is performed repeatedly, uneven deterioration of the catalytic layer on the surface of each electrode due to an uneven electric field can be suppressed. Therefore, the space purification device 1 in this embodiment can suppress a decrease in the electrolysis efficiency of the first diaphragm-equipped electrolysis.

[0065] The first supply tank side cathode 11 and the electrolytic cell side anode 31 are each disposed close to the anion exchange membrane 41. In this specification, "close to" includes both a state in which the first supply tank side cathode 11 and the electrolytic cell side anode 31 are close to the anion exchange membrane 41 with a predetermined gap between them, and a state in which the first supply tank side cathode 11 and the electrolytic cell side anode 31 are in contact with the anion exchange membrane 41.

[0066] The cation exchange membrane 42 is a membranous member that is provided to connect the second supply tank 20 and the electrolytic tank 30 and allows cations to pass therethrough based on a voltage applied between the second supply tank 20 and the electrolytic tank 30. More specifically, when a voltage is applied between the second supply tank 20 and the electrolytic tank 30, second membrane-with-diaphragm electrolysis is performed via the cation exchange membrane 42. By the second membrane-with-diaphragm electrolysis using the second supply tank-side anode 21 and the electrolytic tank-side cathode 32, metal ions contained in the second aqueous solution L2 permeate the cation exchange membrane 42 and are supplied to the third aqueous solution L3 (positive direction of the x-axis, indicated by a thick white arrow).

[0067] The cation exchange membrane 42 in this embodiment is not a type of cation exchange membrane through which cations permeate due to osmotic pressure without using electricity. Furthermore, hydroxide ions, which are anions, do not permeate the cation exchange membrane 42. More specifically, when metal ions contained in the second aqueous solution L2 permeate the cation exchange membrane 42 and are supplied to the third aqueous solution L3 by second membrane-with-diaphragm electrolysis using the second supply tank-side anode 21 and the electrolytic cell-side cathode 32, hydroxide ions, which are anions, do not permeate the cation exchange membrane 42.

[0068] The plane of the second supply tank side anode 21 facing the cation exchange membrane 42 (the yz plane on the positive side of the x-axis) and the plane of the electrolytic cell side cathode 32 facing the cation exchange membrane 42 (the yz plane on the negative side of the x-axis) are arranged opposite each other with the cation exchange membrane 42 interposed therebetween. That is, the electrolytic cell side cathode 32, the cation exchange membrane 42, and the second supply tank side anode 21 are arranged at a predetermined distance along one direction (the x-axis direction) in which metal ions contained in the second aqueous solution L2 permeate the cation exchange membrane 42 and are supplied to the third aqueous solution L3. This arrangement allows a uniform electric field to be generated between the second supply tank side anode 21 and the electrolytic cell side cathode 32. Because electrolysis is generated uniformly, the current between the second supply tank side anode 21 and the electrolytic cell side cathode 32 is also uniformly distributed. Therefore, deterioration of the catalytic layer on the surface of each electrode (the second supply tank-side anode 21 and the electrolytic tank-side cathode 32) occurs uniformly, and therefore, even when electrolysis is repeatedly performed, uneven deterioration of the catalytic layer on the surface of each electrode due to an uneven electric field can be suppressed. Therefore, the space purification device 1 in this embodiment can suppress a decrease in the electrolysis efficiency of the second diaphragm-equipped electrolysis.

[0069] The second supply tank side anode 21 and the electrolytic cell side cathode 32 are disposed close to the cation exchange membrane 42. In this specification, "close to" includes both a state in which the second supply tank side anode 21 and the electrolytic cell side cathode 32 are close to the cation exchange membrane 42 with a predetermined gap therebetween, and a state in which the second supply tank side anode 21 and the electrolytic cell side cathode 32 are in contact with the cation exchange membrane 42.

[0070] As described above, the first supply tank side cathode 11, the anion exchange membrane 41, the electrolytic cell side anode 31, the electrolytic cell side cathode 32, the cation exchange membrane 42, and the second supply tank side anode 21 are arranged at a predetermined interval along one direction (x-axis direction). That is, the anion exchange membrane 41 and the cation exchange membrane 42 are arranged opposite each other. In this specification, the term "predetermined interval" means that the above components are arranged at any interval. That is, the above components may be arranged at different intervals when arranged. More specifically, the interval between the first supply tank side cathode 11 and the anion exchange membrane 41, the interval between the anion exchange membrane 41 and the electrolytic cell side anode 31, the interval between the electrolytic cell side anode 31 and the electrolytic cell side cathode 32, the interval between the electrolytic cell side cathode 32 and the cation exchange membrane 42, and the interval between the cation exchange membrane 42 and the second supply tank side anode 21 may each be different.

[0071] The current control unit 50 controls the current used in the first electrolysis with a diaphragm, the second electrolysis with a diaphragm, and the electrolysis without a diaphragm. The current control unit 50 is equipped with wiring 51, 52, 53, and 54. The wiring 51, 52, 53, and 54 are lines through which current flows. The first supply tank side cathode 11 is electrically connected to the current control unit 50 via wiring 51, the second supply tank side anode 21 via wiring 52, the electrolytic cell side anode 31 via wiring 53, and the electrolytic cell side cathode 32 via wiring 54. A portion of each electrode (the first supply tank side cathode 11, the electrolytic cell side anode 31, the electrolytic cell side cathode 32, and the second supply tank side anode 21) may protrude outside the respective tanks and be connected to the respective wiring.

[0072] Next, the first diaphragm-containing electrolysis unit E1, the second diaphragm-containing electrolysis unit E2 (E2a, E2b), and the diaphragm-less electrolysis unit E3 included in the space purification device 1 according to this embodiment will be described with reference to Figures 2 and 3. The second diaphragm-containing electrolysis unit E2 includes two examples, the second diaphragm-containing electrolysis unit E2a and the second diaphragm-containing electrolysis unit E2b. Therefore, the first example will be described in Figure 2, and the second example will be described in Figure 3.

[0073] <First Example: First Electrolysis Unit with Diaphragm E1, Second Electrolysis Unit with Diaphragm E2a, and Electrolysis Unit without Diaphragm E3> Figure 2 is a partial cross-sectional plan view taken along line II-II in Figure 1, showing a first example of the electrolysis units included in the space purification device 1. In Figure 2, the first electrolysis unit with diaphragm E1 is shown as the area surrounded by a dashed-dotted line rectangle, the second electrolysis unit with diaphragm E2a is shown as the area surrounded by a dashed-dotted line rectangle, and the Electrolysis Unit without Diaphragm E3 is shown as the area surrounded by a broken-line rectangle.

[0074] The first membrane-containing electrolysis unit E1 is provided across the first supply tank 10 and the electrolytic tank 30. The first membrane-containing electrolysis unit E1 includes a first supply tank-side cathode 11, an electrolytic tank-side anode 31, and an anion exchange membrane 41. The first membrane-containing electrolysis unit E1 performs first membrane-containing electrolysis via the anion exchange membrane 41 by passing a first current between the pair of the first supply tank-side cathode 11 and the electrolytic tank-side anode 31.

[0075] The second membrane-based electrolysis unit E2a is provided across the first supply tank 10 and the second supply tank 20. The second membrane-based electrolysis unit E2a includes a first supply tank side cathode 11, a second supply tank side anode 21, an anion exchange membrane 41, and a cation exchange membrane 42. The second membrane-based electrolysis unit E2a performs second membrane-based electrolysis via the anion exchange membrane 41 and the cation exchange membrane 42 by passing a second current between the pair of the first supply tank side cathode 11 and the second supply tank side anode 21.

[0076] The diaphragm-free electrolysis unit E3 is provided in the electrolytic cell 30. The diaphragm-free electrolysis unit E3 includes an electrolytic cell-side anode 31 and an electrolytic cell-side cathode 32. The diaphragm-free electrolysis unit E3 electrolyzes the third aqueous solution without a diaphragm by passing a third current between the pair of the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32, thereby producing hypochlorous acid.

[0077] As described above, in the first example, the first supply cell side cathode 11 is used for the first membrane electrolysis and the second membrane electrolysis, and the electrolytic cell side anode 31 is used for the first membrane electrolysis and the membraneless electrolysis.

[0078] <Second Example: First Diaphragm-Included Electrolysis Unit E1, Second Diaphragm-Included Electrolysis Unit E2b, and Diaphragm-Free Electrolysis Unit E3> Figure 3 is a partial cross-sectional plan view taken along line II-II in Figure 1, illustrating a second example of the electrolysis units included in the space purification device 1. In Figure 3, the first diaphragm-included electrolysis unit E1 is indicated by a dashed-dotted rectangle, the second diaphragm-included electrolysis unit E2b is indicated by a dashed-dotted rectangle, and the diaphragm-free electrolysis unit E3 is indicated by a broken-dashed rectangle. The device configuration of the space purification device 1 in the second example, the first diaphragm-included electrolysis unit E1, and the diaphragm-free electrolysis unit E3 are the same as those in the first example, so their description will be omitted in this example, and only the second diaphragm-included electrolysis unit E2b will be described.

[0079] The second membrane-containing electrolysis unit E2b is provided across the second supply tank 20 and the electrolytic tank 30. The second membrane-containing electrolysis unit E2b includes a second supply tank-side anode 21, an electrolytic tank-side cathode 32, and a cation exchange membrane 42. The second membrane-containing electrolysis unit E2b performs second membrane-containing electrolysis via the cation exchange membrane 42 by passing a second current between the pair of the second supply tank-side anode 21 and the electrolytic tank-side cathode 32.

[0080] As described above, in the second example, the electrolytic cell side anode 31 is used for the first electrolysis with a diaphragm and the electrolysis without a diaphragm, and the electrolytic cell side cathode 32 is used for the second electrolysis with a diaphragm and the electrolysis without a diaphragm.

[0081] The current control unit 50 (see FIG. 1 ) controls the first current used in the first electrolysis with a diaphragm, the second current used in the second electrolysis with a diaphragm, and the third current used in the electrolysis without a diaphragm. In other words, the current control unit 50 controls the first current passed through the first electrolysis unit with a diaphragm E1, the second current passed through the second electrolysis unit with a diaphragm E2 (E2a, E2b), and the third current passed through the electrolysis unit without a diaphragm E3, thereby controlling the chemical reaction occurring in the first electrolysis unit with a diaphragm E1, the chemical reaction occurring in the second electrolysis unit with a diaphragm E2, and the chemical reaction occurring in the electrolysis unit without a diaphragm E3.

[0082] 4 to 6, the chemical reactions occurring in the first electrolysis unit with diaphragm E1, the second electrolysis unit with diaphragm E2, and the non-diaphragm electrolysis unit E3 will be described in detail below. The following describes a case where the first aqueous solution L1 is an aqueous magnesium chloride solution, the second aqueous solution L2 is an aqueous disodium hydrogen phosphate solution, and the third aqueous solution L3 is an aqueous sodium chloride solution.

[0083] [First diaphragm electrolysis unit E1] In the first diaphragm electrolysis unit E1, chemical reactions occur in both the first supply tank-side cathode 11 and the electrolytic cell-side anode 31 via the anion exchange membrane 41. That is, in the first diaphragm electrolysis unit E1, chemical reactions occur in both the first aqueous solution L1 stored in the first supply tank 10 and the third aqueous solution L3 stored in the electrolytic cell 30.

[0084] FIG. 4 shows a list of chemical reactions occurring in the first aqueous solution L1 stored in the first supply tank 10 of the first membrane-equipped electrolysis unit E1, and chemical reactions occurring in the third aqueous solution L3 stored in the electrolysis tank 30.

[0085] When a voltage is applied to the first membrane-containing electrolysis unit E1, a first current flows, electrons move, and the chemical reactions shown in Fig. 4 occur. Note that the chemical reactions shown in Figs. 4(a) to 4(f) that occur in the third aqueous solution L3 stored in the electrolytic cell 30 also occur in the membrane-less electrolysis unit E3.

[0086] First, with reference to FIGS. 4(a) to 4(f), the reactions occurring in the third aqueous solution L3 stored in the electrolytic bath 30 will be described.

[0087] <Electrolytic cell 30 (third aqueous solution L3)> FIG. 4( a): Anion exchange membrane 41. When a voltage is applied to the first membrane-containing electrolysis section E1 and a first current flows, the first current flows between the electrolytic cell-side anode 31 and the first supply cell-side cathode 11, causing the water (H ２ O) to electrons (e － ) contained in the first aqueous solution L1 stored in the first supply tank 10. －) permeates the anion exchange membrane 41 and is supplied to the third aqueous solution L3 stored in the electrolytic cell 30. The chloride ions (Cl － ) is used in the following reaction formula (b) in FIG. 4. In other words, in the third aqueous solution L3, the electrons (e － ) is converted into chloride ions (Cl － ) can be said to be

[0088] Next, as shown in reaction formula (b) and reaction formula (c) of Fig. 4, two types of reactions occur at the electrolytic cell side anode 31: chlorine (liquid) and oxygen (gas). Reaction formula (b) of Fig. 4: Electrolytic cell side anode 31 (chlorine generation reaction) Sodium chloride (NaCl) contained in the sodium chloride aqueous solution, which is the third aqueous solution L3, converts into sodium ions (Na ＋ ) and chloride ions (Cl － 4A, chloride ions (Cl ) are ionized from the first aqueous solution L1 to the third aqueous solution L3 through the anion exchange membrane 41. － ) is supplied to the electrolytic cell anode 31. The chloride ions (Cl － ) and chloride ions (Cl ) supplied from the third aqueous solution L3 － ) is an electron (e － ) and loses chlorine (Cl ２ 4: Electrolytic cell-side anode 31 (oxygen generation reaction) At the electrolytic cell-side anode 31, water (H ２ O) to electrons (e － ) is taken away, and oxygen (O ２ ) and hydrogen ions (H ＋ 4 (d): In the third aqueous solution L3 (hypochlorous acid generation reaction) In the third aqueous solution L3 stored in the electrolytic cell 30, chlorine (Cl ) generated by reaction formula (b) of FIG. ２ ) is the water (H ２ O), hydrolysis occurs, generating hydrochloric acid (HCl) and hypochlorous acid (HClO). Hydrochloric acid (HCl) ionizes in an aqueous solution, generating hydrogen ions (H ＋ ) and chloride ions (Cl －4 (e): Hypochlorous acid generating reaction (equilibrium reaction formula) The equilibrium reaction formula of the hypochlorous acid generating reaction is shown below. － Depending on the increase or decrease of Cl in the electrolytic cell 30, the equilibrium state may shift to the right or to the left. － The current is controlled as described below so that the apparent increase or decrease in the amount of chloride ions does not occur. Equation (f) of FIG. 4: Equation of chloride ion change during electrolysis Equation (f) of FIG. 4 is a single equation that combines reaction equations (b) and (d) of FIG. 4. The chlorine (Cl) generated by reaction equation (b) of FIG. ２ ) is converted into hydrochloric acid (HCl) and hypochlorous acid (HClO) according to reaction formula (d) in FIG. 4.

[0089] Next, with reference to FIGS. 4(g) to 4(i), the reaction occurring in the first aqueous solution L1 stored in the first supply tank 10 will be described.

[0090] <First supply tank 10 (first aqueous solution L1)> FIG. 4( g): When a voltage is applied to the first diaphragm electrolysis unit E1 and a first current flows, chloride ions (Cl ) contained in the first aqueous solution L1 stored in the first supply tank 10 are converted into chloride ions (Cl ). － ) permeates the anion exchange membrane 41 and is supplied to the third aqueous solution L3 stored in the electrolytic cell 30. The chloride ions (Cl － ) is used in the reaction formula (b) in FIG. 4 described above. In addition, when a first current flows between the electrolytic cell-side anode 31 and the first supply cell-side cathode 11, the water (H ２ O) is electron (e － In other words, in the first aqueous solution L1, chloride ions (Cl － ) after the first current flows (after the change), electrons (e － ) The water (H ２ O) is electron (e － The reaction occurring when the first aqueous solution L1 receives water (H ) is shown in the following reaction formula (h) in FIG. 4. Reaction formula (h) in FIG. 4: First supply tank side cathode 11 (hydrogen generation reaction)２ O) is electron (e － ) and hydrogen (H ２ ) and hydroxide ions (OH － ) is generated. Hydrogen volatilizes as gas from the first outlet 13, and hydroxide ions are used in the following reaction formula (i) in FIG. 4. Reaction formula (i) in FIG. 4: In the first aqueous solution L1 (magnesium hydroxide precipitation reaction) Magnesium ions (Mg ２＋ ) and hydroxide ions (OH － ) reacts with magnesium hydroxide (Mg(OH) ２ ) A precipitate is formed.

[0091] Here, magnesium hydroxide (Mg(OH) ２ ) has a solubility product of Ksp = 1.2 x 10 －１１ (mol / L) ３ and is a substance that is extremely difficult to dissolve in aqueous solutions with a pH ranging from neutral to alkaline. For example, the solubility of magnesium hydroxide in a weakly alkaline aqueous solution with a pH of 10 is only 1.2 × 10 －３ In the first aqueous solution L1 of the first supply tank 10, hydroxide ions (OH － ) is magnesium hydroxide (Mg(OH) ２ ) precipitate in the first aqueous solution L1. － ) and the increase in the pH of the first aqueous solution L1 can be suppressed.

[0092] Furthermore, when a magnesium chloride aqueous solution is used as the first aqueous solution L1, the pH of the saturated magnesium hydroxide aqueous solution, in which the magnesium hydroxide produced after the first diaphragm electrolysis is saturated, is 10.36, as determined from the solubility product Ksp. Therefore, even after the first diaphragm electrolysis is performed over a long period of time, the pH of the first aqueous solution L1 can be maintained in a weakly alkaline state of up to 10.36 or less. In other words, when a magnesium chloride aqueous solution is used as the first aqueous solution L1, the pH of the first aqueous solution L1 can be prevented from becoming strongly alkaline, i.e., 11 or more. Therefore, the first aqueous solution L1 stored in the first supply tank 10 can be prevented from becoming strongly alkaline after electrolysis, thereby providing a space purification device 1 with improved safety.

[0093] Furthermore, for example, the space purification device 1 according to the present embodiment may be installed by a contractor. After use of the space purification device 1, the space purification device 1 may be overturned or dropped when the contractor removes the installed space purification device or during transportation after removal. Here, when a magnesium chloride aqueous solution is used as the first aqueous solution L1, the first aqueous solution L1 after the electrolysis reaction is a weakly alkaline magnesium hydroxide aqueous solution. Therefore, even if the first aqueous solution L1 leaks outside the space purification device 1 due to overturning or dropping, safety can be improved compared to space purification devices using a sodium chloride aqueous solution.

[0094] Next, chemical reactions occurring in the second diaphragm electrolysis section will be described with reference to Figures 5 and 6. Regarding the second diaphragm electrolysis section, both the second diaphragm electrolysis section E2a (see Figure 2 for the configuration) which is a first example of the second diaphragm electrolysis section, and the second example of the second diaphragm electrolysis section E2b (see Figure 3 for the configuration) will be described with reference to Figure 5. First, the first example of the second diaphragm electrolysis section E2a will be described.

[0095] [Second diaphragm electrolysis unit E2a] In the second diaphragm electrolysis unit E2a, reactions occur in both the first supply tank-side cathode 11 and the second supply tank-side anode 21 via the anion exchange membrane 41 and the cation exchange membrane 42. That is, in the second diaphragm electrolysis unit E2a, chemical reactions occur in both the first aqueous solution L1 stored in the first supply tank 10 and the second aqueous solution L2 stored in the second supply tank 20. Through the chemical reactions in the second diaphragm electrolysis unit E2a, chloride ions are supplied from the first aqueous solution L1 to the third aqueous solution L3 stored in the electrolytic tank 30, and metal ions are supplied from the second aqueous solution L2 to the third aqueous solution L3 stored in the electrolytic tank 30. For example, when the second aqueous solution L2 is a disodium hydrogen phosphate aqueous solution, sodium ions are supplied from the second aqueous solution L2 to the third aqueous solution L3.

[0096] Chloride ions are supplied from the first aqueous solution L1 to the third aqueous solution L3 stored in the electrolytic cell 30 by the reaction in the second diaphragm electrolysis unit E2a, causing the hypochlorous acid generation reaction described using reaction formula (d) in Fig. 4 in the third aqueous solution L3. In other words, when the second diaphragm electrolysis unit E2a is used, chloride ions are supplied from the first aqueous solution L1 stored in the first supply tank 10 to the third aqueous solution L3 stored in the electrolytic cell 30 by both the first diaphragm electrolysis unit E1 and the second diaphragm electrolysis unit E2a. The second diaphragm electrolysis unit E2b, which will be described later, does not supply chloride ions from the first aqueous solution L1 to the third aqueous solution L3. Therefore, for example, when the amount of the first current is a predetermined value, using the second diaphragm electrolysis unit E2a allows more chloride ions to be supplied to the electrolytic cell 30 than using the second diaphragm electrolysis unit E2b.

[0097] FIG. 5 shows a list of chemical reactions occurring in the first aqueous solution L1 stored in the first supply tank 10 of the second membrane-equipped electrolysis section E2a, and chemical reactions occurring in the second aqueous solution L2 stored in the second supply tank 20.

[0098] When a voltage is applied to the second membrane-containing electrolysis unit E2a, a second current flows, electrons are transferred, and the chemical reaction shown in Fig. 5 occurs. First, with reference to Figs. 5(a) to 5(c), the chemical reaction occurring in the first aqueous solution L1 stored in the first supply tank 10 will be described. Note that the chemical reaction occurring in the first aqueous solution L1 stored in the first supply tank 10 shown in Figs. 5(a) to 5(c) is substantially the same as the chemical reaction described using Figs. 4(g) to 4(i).

[0099] <First Supply Tank 10 (First Aqueous Solution L1)> FIG. 5( a): When a voltage is applied to the second diaphragm electrolysis unit E2 and a second current flows, chloride ions (Cl ) contained in the first aqueous solution L1 stored in the first supply tank 10 are converted into chloride ions (Cl ). － ) permeates the anion exchange membrane 41 and is supplied to the third aqueous solution L3 stored in the electrolytic cell 30. The chloride ions (Cl － ) is used in the reaction formula (b) of FIG. 4 described above. In addition, when a second current flows between the first supply tank side cathode 11 and the second supply tank side anode 21, the water (H ２ O) is electron (e － In other words, in the first aqueous solution L1, chloride ions (Cl － ) after the first current flows (after the change), electrons (e － ) The water (H ２ O) is electron (e － 5B: First supply tank side cathode 11 (hydrogen generation reaction) At the first supply tank side cathode 11, the water (H ２ O) is electron (e － ) and hydrogen (H ２ ) and hydroxide ions (OH － ) is generated. Hydrogen volatilizes as gas from the first outlet 13, and hydroxide ions are used in the following reaction formula (c) in FIG. 5. Reaction formula (c) in FIG. 5: In the first aqueous solution L1 (magnesium hydroxide precipitation reaction) Magnesium ions (Mg２＋ ) and hydroxide ions (OH － ) reacts with magnesium hydroxide (Mg(OH) ２ ) A precipitate is formed.

[0100] Next, with reference to FIGS. 5(d) and 5(e), the reaction occurring in the second aqueous solution L1 stored in the second supply tank 20 will be described.

[0101] <Second supply tank 20 (first aqueous solution L2)> Reaction formula (d) in FIG. 5: Second supply tank side anode 21 (oxygen generation reaction) In the second supply tank side anode 21, water (H ２ O) to electrons (e － ) is taken away, and oxygen (O ２ ) and hydrogen ions (H ＋ ) is generated. Oxygen volatilizes as gas from the second outlet 23. When a voltage is applied to the second membrane electrolysis section E2a and a second current flows, the sodium ions (Na ＋ ) permeates the cation exchange membrane 42 and is supplied to the third aqueous solution L3. In addition, the second current flows between the first supply tank side cathode 11 and the second supply tank side anode 21, and the electrons (e － ) moves from the second supply tank side anode 21 to the first aqueous solution L1 through the first supply tank side cathode 11. In other words, sodium ions (Na ＋ ) and electrons (e － ) is lost from the second aqueous solution L2 after the second current flows (after the change). ２ O) is electron (e － The reaction that occurs when the cation exchange reaction (C) is received is as explained using reaction formula (b) in FIG. 5.

[0102] [Second membrane electrolysis unit E2b] Next, a second example of the second membrane electrolysis unit E2b will be described with reference to Fig. 6. Fig. 6 shows a list of chemical reactions occurring in the second aqueous solution L2 stored in the second supply tank 20 of the second membrane electrolysis unit E2b, and chemical reactions occurring in the third aqueous solution L3 stored in the electrolytic tank 30.

[0103] In the second membrane-equipped electrolysis unit E2b, reactions occur in both the second supply tank-side anode 21 and the electrolytic tank-side cathode 32 via the cation exchange membrane 42. That is, in the second membrane-equipped electrolysis unit E2b, reactions occur in both the second aqueous solution L2 stored in the second supply tank 20 and the third aqueous solution L3 stored in the electrolytic tank 30. First, with reference to FIGS. 6( a) and 6(b), the reactions occurring in the second aqueous solution L2 stored in the second supply tank 20 will be described. The reactions occurring in the second aqueous solution L2 shown in FIGS. 6( a) and 6(b) are substantially the same as the chemical reactions described using FIGS. 5(d) and 5(e).

[0104] <Second Supply Tank 20 (Second Aqueous Solution L2)> Reaction Formula (a) in FIG. 6: Second Supply Tank Side Anode 21 (Oxygen Evolution Reaction) In the second supply tank side anode 21, water (H ２ O) to electrons (e － ) is taken away, and oxygen (O ２ ) and hydrogen ions (H ＋ ) is generated. The generated oxygen volatilizes as gas from the second outlet 23. - (b) of FIG. 6: When a voltage is applied to the second membrane electrolysis section E2b and a second current flows, sodium ions (Na ＋ ) permeates the cation exchange membrane 42 and is supplied to the third aqueous solution L3. In addition, when a second current flows between the second supply tank side anode 21 and the electrolytic tank side cathode 32, the electrons (e － ) moves from the second supply cell side anode 21 to the third aqueous solution L3 through the electrolytic cell side cathode 32. In other words, the sodium ions (Na ＋ ) and electrons (e －) is lost from the second aqueous solution L2 after the second current flows (after the change). ２ O) is electron (e － The reaction that occurs when the cation exchange reaction (C) is received will be explained below using reaction formula (d) in FIG.

[0105] Next, with reference to FIGS. 6(c) and 6(d), the reaction occurring in the third aqueous solution L3 stored in the electrolytic bath 30 will be described.

[0106] <Electrolytic cell 30 (third aqueous solution L3)> - Cation exchange membrane 42 in FIG. 6 (c) As described above in FIG. 6 (b), when a voltage is applied to the second membrane electrolysis section E2b and the second current flows, sodium ions (Na ＋ ) and electrons (e － ) is supplied to the third aqueous solution L3. In other words, before the second current flows (before the change), the third aqueous solution L3 does not contain sodium ions and electrons derived from the second aqueous solution L2, but after the second current flows (after the change), sodium ions and electrons are supplied from the second aqueous solution L2 to the third aqueous solution L3 via the cation exchange membrane 42. Reaction formula (d) in Figure 6: Electrolytic cell-side cathode 32 (hydrogen generation reaction) At the electrolytic cell-side cathode 32, the sodium ions and electrons of the third aqueous solution L3 (H ２ O) is electron (e － ) and hydrogen (H ２ ) and hydroxide ions (OH － ) occurs.

[0107] Next, the chemical reaction occurring in the diaphragm-free electrolysis section E3 will be described with reference to Fig. 7. In the diaphragm-free electrolysis section E3, a reaction occurs in the third aqueous solution L3 stored in the electrolytic cell 30, not via an ion exchange membrane, at both the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32. That is, in the diaphragm-free electrolysis section E3, a reaction occurs only in the third aqueous solution L3 stored in the electrolytic cell 30.

[0108] [Diaphragm-free electrolysis unit E3 (electrolytic cell 30)] Fig. 7 shows a list of reaction formulas that occur in the third aqueous solution L3 stored in the electrolytic cell 30 of the diaphragm-free electrolysis unit E3. When a voltage is applied to the diaphragm-free electrolysis unit E3, a third current flows, electrons are transferred, and chemical reactions shown in reaction formulas (a) to (g) in Fig. 7 occur.

[0109] Before describing the membrane-less electrolysis section E3, the changes will be described. First, chloride ions are supplied from the first aqueous solution L1, and sodium ions and electrons are supplied from the second aqueous solution L2 to the third aqueous solution L3 stored in the electrolytic cell 30. - Fig. 7(a): Anion exchange membrane 41 As described above, when a voltage is applied to the first membrane-with electrolysis section E1 and the second membrane-with electrolysis section E2a and the first and second currents flow, the third aqueous solution L3 stored in the electrolytic cell 30 generates electrons (e － ) is lost. － In the third aqueous solution L3, which has lost its chloride ions (Cl), a force that maintains electrical neutrality acts, and negatively charged chloride ions (Cl － ) is supplied from the first aqueous solution L1 stored in the first supply tank 10 to the third aqueous solution L3 stored in the electrolytic cell 30 through the anion exchange membrane 41. In the third aqueous solution L3, the electrons (e － ) changes to chloride ions (Cl － ) can be said to be

[0110] Next, as shown in reaction formulas (b) and (c) of Fig. 7, two types of reactions occur at the electrolytic cell-side anode 31: chlorine (liquid) and oxygen (gas). Reaction formula (b) of Fig. 7: Electrolytic cell-side anode 31 (chlorine generation reaction) Sodium chloride (NaCl) contained in the sodium chloride aqueous solution, which is the third aqueous solution L3, converts into sodium ions (Na ＋ ) and chloride ions (Cl － 7A, chloride ions (Cl ) are ionized from the first aqueous solution L1 to the third aqueous solution L3 through the anion exchange membrane 41. － ) is supplied to the electrolytic cell anode 31. The chloride ions (Cl － ) and chloride ions (Cl ) supplied from the third aqueous solution L3 － ) is an electron (e － ) and loses chlorine (Cl２ 7: Electrolytic cell-side anode 31 (oxygen generation reaction) At the electrolytic cell-side anode 31, water (H ２ O) to electrons (e － ) is taken away, and oxygen (O ２ ) and hydrogen ions (H ＋ 7(d) Cation exchange membrane 42 When a voltage is applied to the second membrane electrolysis section E2a or the second membrane electrolysis section E2b and a second current flows, sodium ions (Na ＋ ) and electrons (e － ) is supplied to the third aqueous solution L3. In other words, before the second current flows (before the change), the third aqueous solution L3 does not contain sodium ions and electrons derived from the second aqueous solution L2, but after the second current flows (after the change), sodium ions and electrons are supplied from the second aqueous solution L2 to the third aqueous solution L3 via the cation exchange membrane 42. Reaction formula (e) in Figure 7: Electrolytic cell-side cathode 32 (hydrogen generation reaction) At the electrolytic cell-side cathode 32, the sodium ions and electrons of the third aqueous solution L3 (H ２ O) is electron (e － ) and hydrogen (H ２ ) and hydroxide ions (OH － 7 : In the third aqueous solution L3 (hypochlorous acid generation reaction) In the third aqueous solution L3 stored in the electrolytic cell 30, chlorine (Cl ) generated by reaction formula (b) of FIG. ２ ) is the water (H ２ O), hydrolysis occurs, generating hydrochloric acid (HCl) and hypochlorous acid (HClO). Hydrochloric acid (HCl) ionizes in an aqueous solution, generating hydrogen ions (H ＋ ) and chloride ions (Cl － ) In addition, hydrogen ions generated by reaction formula (c) in FIG. 7 are present in the third aqueous solution L3. ＋ ) is the hydroxide ion (OH) generated in reaction formula (e) of FIG. － ) to form water. That is, the pH of the third aqueous solution L3 may decrease with the generation of hydrogen ions in the third aqueous solution L3, but the hydrogen ions (H ＋) and hydroxide ions (OH － ) reacts with the first aqueous solution L1, thereby suppressing a decrease in pH of the third aqueous solution L3 due to an increase in hydrogen ions. Reaction formula (g) in FIG. 7: Hypochlorous acid generating reaction (equilibrium reaction formula) The equilibrium reaction formula for the hypochlorous acid generating reaction is shown below. － Depending on the increase or decrease of Cl in the electrolytic cell 30, the equilibrium state may shift to the right or to the left. － The current is controlled as described below so that the apparent increase or decrease in the amount of chloride ions does not occur. Equation (h) of FIG. 7: Equation of chloride ion change during electrolysis Equation (h) of FIG. 7 is a single equation that combines reaction equations (b) and (f) of FIG. 7. The chlorine (Cl) generated by reaction equation (b) of FIG. ２ ) is converted into hydrochloric acid (HCl) and hypochlorous acid (HClO) according to reaction formula (f) in FIG. 7.

[0111] The current control unit 50 controls the chemical reaction. Here, due to bubbling of the third aqueous solution L3 during the purification operation of the space purification device 1, the sodium chloride aqueous solution contained in the third aqueous solution L3 splashes onto the inner wall surface of the electrolytic cell 30 located in the electrolytic cell-side inner space 35 and adheres as water droplets. When only the water evaporates from the adhered water droplets, the sodium chloride remaining on the inner wall surface of the electrolytic cell 30 may crystallize into white, which is called salt splashing. In addition, salt splashing also includes the mixture of the mixed air M discharged from the discharge port 37 and the sodium chloride aqueous solution flying into the external space R as droplets. Therefore, in the electrolytic cell 30, (1) a reduction in chloride ions due to diaphragm-less electrolysis in the diaphragm-less electrolysis unit E3, and (2) a reduction in chloride ions (Cl ) due to salt splashing. － ) may decrease.

[0112] The current control performed in the first and second examples, which have different configurations of the second membrane electrolyzing section E2, will be described below.

[0113] <First Example: Case of First Electrolysis Unit E1 with Diaphragm, Second Electrolysis Unit E2a with Diaphragm, and Electrolysis Unit E3 without Diaphragm> The current control unit 50 (1) controls the first current so as to replenish chloride ions contained in the third aqueous solution L3 that have been reduced by diaphragm-less electrolysis in the diaphragm-less electrolysis unit E3, thereby causing chloride ions contained in the first aqueous solution L1 to permeate through the anion exchange membrane 41 and be supplied to the third aqueous solution L3. Furthermore, when the third aqueous solution L3 is a sodium chloride aqueous solution, the current control unit 50 (2) controls the second current of the second diaphragm-with-membrane electrolysis unit E2a so as to replenish chloride ions and sodium ions contained in the third aqueous solution L3 that have been reduced by salt splashing, thereby causing chloride ions contained in the first aqueous solution L1 to permeate through the anion exchange membrane 41 and be supplied to the third aqueous solution L3, and sodium ions contained in the second aqueous solution L2 to be supplied to the third aqueous solution L3.

[0114] The current control unit 50 supplies the first current, the second current, and the third current at a predetermined ratio so as to replenish the chloride ions that have decreased in the third aqueous solution L3 and maintain the hypochlorous acid concentration of the third aqueous solution at a predetermined concentration.

[0115] <Second Example: Case of First Electrolysis Unit with Diaphragm E1, Second Electrolysis Unit with Diaphragm E2b, and Electrolysis Unit without Diaphragm E3> The current control unit 50 (1) controls the first current so as to replenish chloride ions contained in the third aqueous solution L3 that have been reduced by diaphragm-less electrolysis in the diaphragm-less electrolysis unit E3, thereby causing chloride ions contained in the first aqueous solution L1 to pass through the anion exchange membrane 41 and be supplied to the third aqueous solution L3. Furthermore, when the third aqueous solution L3 is a sodium chloride aqueous solution, the current control unit 50 (2) controls the first current and the second current of the second electrolysis unit with diaphragm E2b so as to replenish chloride ions and sodium ions contained in the third aqueous solution L3 that have been reduced by salt splashing, thereby supplying chloride ions contained in the first aqueous solution L1 and sodium ions contained in the second aqueous solution L2 to the third aqueous solution L3.

[0116] The current control unit 50 supplies the first current, the second current, and the third current at a predetermined ratio so as to replenish the chloride ions that have decreased in the third aqueous solution L3 and maintain the hypochlorous acid concentration of the third aqueous solution at a predetermined concentration.

[0117] The configuration of the current control unit 50 will now be described with reference to Fig. 8. Fig. 8 is a block diagram showing the current control unit 50 according to the embodiment. As shown in Fig. 8, the current control unit 50 includes a voltage acquisition unit 50a, a calculation unit 50b, and an estimation unit 50c.

[0118] The voltage acquiring unit 50a acquires the voltage applied between the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32. The voltage acquiring unit 50a is, for example, a voltmeter. The calculation unit 50b calculates the conductivity of the third aqueous solution L3 based on the voltage acquired by the voltage acquiring unit 50a. The estimation unit 50c estimates the chloride ion concentration of the third aqueous solution L3 based on the conductivity of the third aqueous solution L3 calculated by the calculation unit 50b. Three types of control examples of current control by the current control unit 50 will be described below. Note that similar control is performed in both the first and second examples, which have different configurations of the second diaphragm electrolysis. In both the first and second examples, which have different configurations for the second membrane electrolysis, before the current control unit 50 changes the current proportions of the first current (first membrane electrolysis), the second current (second membrane electrolysis), and the third current (non-membrane electrolysis), the current proportion of the third current is the largest, followed by the current proportion of the first current between the third current and the second current, and the current proportion of the second current is the smallest, which is a magnitude relationship.

[0119] <First Example: In the Case of the First Electrolysis Unit with Diaphragm E1, the Second Electrolysis Unit with Diaphragm E2a, and the Electrolysis Unit without Diaphragm E3> [1. When the First Current, the Second Current, and the Third Current are Simultaneously Passed] When the first current, the second current, and the third current are simultaneously passed, the current control unit 50 performs control to change or not change the current ratios in the following (1) to (3). (1) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimating unit 50c is lower than a predetermined concentration: The current ratios of the first current, the second current, and the third current are changed so as to increase the amount of chloride ions that permeate from the first aqueous solution L1 through the anion exchange membrane 41 and are supplied to the third aqueous solution L3. More specifically, the current ratio of the first current is increased or not changed, the current ratio of the second current is increased, and the current ratio of the third current is not increased or not changed. In the first example, by passing the first current, chloride ions are supplied from the first aqueous solution L1 stored in the first supply tank 10 to the third aqueous solution L3 stored in the electrolytic tank 30. Furthermore, by passing the second current, chloride ions are also supplied from the first aqueous solution L1 stored in the first supply tank 10 to the third aqueous solution L3 stored in the electrolytic tank 30. On the other hand, the second current flowing in the second diaphragm electrolysis unit E2b described below does not supply chloride ions from the first aqueous solution L1 to the third aqueous solution L3. Therefore, when the second diaphragm electrolysis unit E2a is used, more chloride ions can be supplied to the electrolytic tank 30 than when the second diaphragm electrolysis unit E2b is used.

[0120] Furthermore, when it is desired to supply chloride ions from the third aqueous solution to the first aqueous solution so as to increase the supply amount of chloride ions by a predetermined amount, in the case where the second membrane electrolysis unit E2a is used, a predetermined amount of chloride ions can be supplied from the third aqueous solution to the first aqueous solution by increasing only the second current or by increasing both the first current and the second current.

[0121] On the other hand, when the second membrane electrolysis unit E2b described below is used, if it is desired to supply chloride ions from the third aqueous solution to the first aqueous solution so as to increase the supply amount of chloride ions by a predetermined amount, it is necessary to supply a predetermined amount of chloride ions from the third aqueous solution to the first aqueous solution by increasing the first current amount of the first membrane electrolysis.

[0122] Here, if the first current amount of the first diaphragm electrolysis and the second current amount of the second diaphragm electrolysis are increased so as to increase the amount of chloride ions permeating from the first aqueous solution L1 through the anion exchange membrane 41 and supplied to the third aqueous solution L3, hydrogen ions in the third aqueous solution L3 increase due to the oxygen generation reaction at the electrolytic cell anode 31 (see FIG. 7( c) ). This increase in hydrogen ions may decrease the pH of the third aqueous solution L3, thereby suppressing the generation of hypochlorous acid. Therefore, in the first example, by increasing both the first current and the second current, a predetermined amount of chloride ions can be supplied from the first aqueous solution to the third aqueous solution. Therefore, compared to the case where the second diaphragm electrolysis unit E2b in the second example is used, the increase in hydrogen ions in the third aqueous solution L3 that occurs with an increase in the current ratio of the first current (increase in the current amount) can be suppressed, and the decrease in pH in the third aqueous solution L3 can be suppressed. Note that the second diaphragm electrolysis unit E2b performs a separate control to suppress the decrease in pH in the third aqueous solution L3. This control will be described later. (2) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is higher than a predetermined concentration: The first current, the second current, and the third current are changed so as to reduce the amount of chloride ions that permeate from the first aqueous solution L1 through the anion exchange membrane 41 and are supplied to the third aqueous solution L3. More specifically, the current proportion of the first current is decreased or not changed, the current proportion of the second current is decreased, and the current proportion of the third current is not changed. (3) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is a predetermined concentration: The current proportions of the first current, the second current, and the third current are not changed.

[0123] [2. Controlling the First and Second Currents Simultaneously While Passing the Third Current at a Predetermined Value] When the current control unit 50 controls the first and second currents while passing the third current at a predetermined value, the current control unit 50 performs the following controls (1) to (3). (1) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is lower than a predetermined concentration: The first and second currents are passed so as to increase the amount of chloride ions that permeate from the first aqueous solution L1 through the anion exchange membrane 41 and are supplied to the third aqueous solution L3. For example, the first and third currents are passed at predetermined values, and the second current is increased so as to increase the amount of chloride ions that permeate from the first aqueous solution L1 through the anion exchange membrane 41 and are supplied to the third aqueous solution L3. Furthermore, the second current may be stopped if the chloride ion concentration of the third aqueous solution L3 is equal to or higher than the predetermined concentration. If the second current has been stopped, the second current is released and the second current is passed so as to increase the amount of chloride ions that are supplied to the third aqueous solution L3. (2) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is higher than a predetermined concentration: the first current and the second current are stopped so as to stop the supply of chloride ions from the second aqueous solution L2 to the third aqueous solution L3. (3) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is a predetermined concentration: the current ratio of the first current, the second current, and the third current is not changed.

[0124] [3. When the First Current and the Second Current, or the Third Current are Passed] When the current control unit 50 passes the first current, the second current, or the third current, the current control unit 50 performs the following controls (1) to (3). (1) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is lower than a predetermined concentration: The third current is stopped and the first current and the second current are passed simultaneously so as to increase the amount of chloride ions that permeate through the anion exchange membrane 41 from the first aqueous solution L1 and are supplied to the third aqueous solution L3. (2) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is higher than a predetermined concentration: The first current and the second current are stopped and the third current is passed simultaneously so as to stop the supply of chloride ions from the first aqueous solution L1 to the third aqueous solution L3. (3) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is a predetermined concentration: The current ratio of the first current, the second current, and the third current is not changed.

[0125] As described above, the current control unit 50 controls the first current, the second current, and the third current, thereby supplying the necessary amount of chloride ions to the third aqueous solution L3 stored in the electrolytic cell 30, and maintaining the hypochlorous acid concentration in the third aqueous solution L3 at a predetermined concentration.

[0126] <Second Example: In the Case of the First Electrolysis Unit E1 with Diaphragm, the Second Electrolysis Unit E2b with Diaphragm, and the Electrolysis Unit E3 without Diaphragm> [1. When the First Current, the Second Current, and the Third Current are Simultaneously Passed] When the first current, the second current, and the third current are simultaneously passed, the current control unit 50 performs control to change or not change the current ratios in the following (1) to (3). (1) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimating unit 50c is lower than a predetermined concentration: The current ratios of the first current, the second current, and the third current are changed so as to increase the amount of chloride ions that permeate from the first aqueous solution L1 through the anion exchange membrane 41 and are supplied to the third aqueous solution L3. More specifically, the current ratio of the first current is increased, and the current ratio of the second current is increased so as to correspond to the increase in the current ratio of the first current, and the current ratio of the third current is not increased or changed.

[0127] Here, when the first current amount of the first diaphragm electrolysis is increased so as to increase the amount of chloride ions that permeate the anion exchange membrane 41 from the first aqueous solution L1 and are supplied to the third aqueous solution L3, hydrogen ions in the third aqueous solution L3 increase due to the oxygen generation reaction (see FIG. 7( c)) at the electrolytic cell-side anode 31. When the hydrogen ions increase, the pH of the third aqueous solution L3 decreases, and there is a risk that the generation of hypochlorous acid will be suppressed. Therefore, in the second example, by increasing the current rate of the second current so as to correspond to the increase in the current rate of the first current, the amount of current flowing to the electrolytic cell-side cathode 32 also increases, and hydroxide ions (OH － ) is promoted (see FIG. 7(e)).

[0128] Therefore, the hydrogen ions increased by increasing the current rate of the first current react with hydroxide ions generated by increasing the current rate of the second current to form water. Therefore, by increasing the current rate of the second current in proportion to the increase in the current rate of the first current, a decrease in the pH of the third aqueous solution L3 due to an increase in hydrogen ions can be suppressed. (2) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is higher than a predetermined concentration: The first current, the second current, and the third current are changed so as to reduce the amount of chloride ions that permeate the anion exchange membrane 41 from the first aqueous solution L1 and are supplied to the third aqueous solution L3. More specifically, the current rate of the first current is decreased, the current rate of the second current is decreased, and the current rate of the third current is not increased or changed. (3) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is a predetermined concentration: The current rates of the first current, the second current, and the third current are not changed.

[0129] [2. Controlling the First and Second Currents Simultaneously While Passing the Third Current at a Predetermined Value] When the current control unit 50 controls the first and second currents while passing the third current at a predetermined value, the current control unit 50 performs the following controls (1) to (3). (1) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is lower than a predetermined concentration: The first and second currents are passed so as to increase the amount of chloride ions that permeate from the first aqueous solution L1 through the anion exchange membrane 41 and are supplied to the third aqueous solution L3. For example, the first and third currents are passed at predetermined values, and the second current is increased so as to increase the amount of chloride ions that permeate from the first aqueous solution L1 through the anion exchange membrane 41 and are supplied to the third aqueous solution L3. Furthermore, the second current may be stopped if the chloride ion concentration of the third aqueous solution L3 is equal to or higher than the predetermined concentration. If the second current has been stopped, the second current is released and the second current is passed so as to increase the amount of chloride ions that are supplied to the third aqueous solution L3. (2) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is higher than a predetermined concentration: the first current and the second current are stopped so as to stop the supply of chloride ions from the second aqueous solution L2 to the third aqueous solution L3. (3) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is a predetermined concentration: the current ratio of the first current, the second current, and the third current is not changed.

[0130] [3. When the First Current and the Second Current, or the Third Current are Passed] When the current control unit 50 passes the first current, the second current, or the third current, the current control unit 50 performs the following controls (1) to (3). (1) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is lower than a predetermined concentration: The third current is stopped and the first current and the second current are passed simultaneously so as to increase the amount of chloride ions that permeate through the anion exchange membrane 41 from the first aqueous solution L1 and are supplied to the third aqueous solution L3. (2) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is higher than a predetermined concentration: The first current and the second current are stopped and the third current is passed simultaneously so as to stop the supply of chloride ions from the first aqueous solution L1 to the third aqueous solution L3. (3) When the chloride ion concentration of the third aqueous solution L3 estimated by the estimation unit 50c is a predetermined concentration: The current ratio of the first current, the second current, and the third current is not changed.

[0131] As described above, the current control unit 50 controls the first current, the second current, and the third current, thereby supplying the necessary amount of chloride ions to the third aqueous solution L3 stored in the electrolytic cell 30, and maintaining the hypochlorous acid concentration in the third aqueous solution L3 at a predetermined concentration.

[0132] In the above-mentioned "1. When the first current, the second current, and the third current are simultaneously passed," if there is an increase or decrease in the chloride ion concentration of the third aqueous solution L3, the current ratios of the first current, the second current, and the third current are changed. Because the first current, the second current, and the third current are passed simultaneously, it is possible to minimize the increase or decrease in the chloride ion concentration of the third aqueous solution L3 and maintain it at an optimal predetermined concentration.

[0133] In the above-mentioned "2. When the third current is passed at a predetermined value while the first and second currents are controlled," the first and second currents are mainly passed or stopped when the chloride ion concentration of the third aqueous solution L3 increases or decreases. In the above-mentioned "3. When the first and second currents or the third current are passed," when the chloride ion concentration of the third aqueous solution L3 increases or decreases, either the first and second currents or the third current is passed and the other is stopped. Therefore, the chloride ion concentration of the third aqueous solution L3 can be maintained at a predetermined concentration. In the above-mentioned cases 2 and 3, it is only necessary to control either the first and second currents or the third current, and therefore current control is easy.

[0134] As described above, the chloride ions consumed by the third aqueous solution L3 can be appropriately supplied from the first aqueous solution L1, thereby providing the space purification device 1 capable of stably generating a desired amount of hypochlorous acid gas. Therefore, the space purification device 1 can be provided that can stably generate a desired amount of hypochlorous acid gas for a long period of time, such as one year, without externally supplying an aqueous solution containing chloride ions.

[0135] It is also possible to provide a plurality of current control units 50 and control the first current, the second current, and the third current separately.

[0136] Furthermore, if the current control unit 50 does not include the estimation unit 50c, a memory unit may be provided instead of the estimation unit 50c, which stores a correspondence relationship between the decrease in chloride ions due to membraneless electrolysis and salt splashing and a predetermined time. Based on the memory unit, the current control unit 50 may perform control to increase the current ratio of the first current and / or the second current in order to supply chloride ions from the first aqueous solution L1 to the third aqueous solution L3 when the predetermined time has elapsed.

[0137] When membraneless electrolysis is performed in the electrolytic cell 30 at room temperature and normal pressure, the electrolyte of the third aqueous solution L3 is not used in electrolysis, and oxygen and chlorine are mainly generated from the anode. The electrolyte does not react with hypochlorous acid to reduce the concentration of hypochlorous acid, and is electrically conductive and does not react with the electrodes, the electrolytic cell, or the anion exchange membrane. More specifically, in addition to the third aqueous solution L3 described above, the third aqueous solution L3 may be, for example, a metal chloride aqueous solution, a hydroxide salt aqueous solution, an acid salt aqueous solution, a phosphate aqueous solution, or a combination thereof. The metal chloride aqueous solution may be, for example, a dilute calcium chloride aqueous solution or a dilute magnesium chloride aqueous solution. The hydroxide salt aqueous solution may be, for example, a dilute sodium hydroxide aqueous solution or a dilute potassium hydroxide aqueous solution of 0.4 wt % (0.1 mol / L) or less. The acid salt aqueous solution may be, for example, a dilute hydrochloric acid aqueous solution of 0.4 wt % (0.1 mol / L) or less. The phosphate aqueous solution may be, for example, a disodium hydrogen phosphate aqueous solution, a sodium dihydrogen phosphate aqueous solution, a dipotassium hydrogen phosphate aqueous solution, or a potassium dihydrogen phosphate aqueous solution. As a specific example of a combination of the first aqueous solution L1, the pH may be adjusted by combining a dilute sodium chloride aqueous solution with a dilute sodium hydroxide aqueous solution.

[0138] As described above, the space purification device 1 according to the embodiment can provide the following effects.

[0139] The space purification device 1 according to the present embodiment includes a first supply tank 10 for storing a first aqueous solution L1 containing chloride ions and for supplying the chloride ions contained in the first aqueous solution L1 to a third aqueous solution L3 by passing them through an anion exchange membrane 41 through a first diaphragm-equipped electrolysis unit, a second supply tank 20 for storing a second aqueous solution L2 containing at least one metal ion selected from the group consisting of sodium ions, lithium ions, and potassium ions and for supplying the metal ions contained in the second aqueous solution L2 to a third aqueous solution L3 by passing them through a cation exchange membrane 42 through a second diaphragm-equipped electrolysis unit, and an electrolytic cell 30 for storing the third aqueous solution L3 containing chloride ions and for producing hypochlorous acid by electrolyzing the third aqueous solution L3 without a diaphragm. The space purification device 1 according to the present disclosure having the above configuration performs a purification operation in which air introduced from an external space R flows through the electrolytic cell 30 and is released into the external space R together with hypochlorous acid.

[0140] With the above configuration, chloride ions contained in the first aqueous solution L1 stored in the first supply tank 10 permeate through the anion exchange membrane 41 and are supplied to the third aqueous solution L3 stored in the electrolytic tank 30. Therefore, it is possible to provide the space purification device 1 that can stably generate a desired amount of hypochlorous acid gas without supplying an aqueous solution containing chloride ions from the outside for a long period of time.

[0141] In the space purification device 1 according to this embodiment, as a first example, the first supply tank 10 includes a first supply tank-side cathode 11, the second supply tank 20 includes a second supply tank-side anode 21, and the electrolytic cell 30 includes an electrolytic cell-side anode 31 and an electrolytic cell-side cathode 32. The electrolysis system also includes a first membrane-with-diaphragm electrolysis unit E1, which is provided across the electrolytic cell 30 and the first supply cell 10 and performs first membrane-with-diaphragm electrolysis via the anion exchange membrane 41 by passing a first current between the electrolytic cell-side anode 31 and the first supply cell-side cathode 11; a second membrane-with-diaphragm electrolysis unit E2a, which is provided across the first supply cell 10 and the second supply cell 20 and performs second membrane-with-diaphragm electrolysis via the anion exchange membrane 41 and the cation exchange membrane 42 by passing a second current between the first supply cell-side cathode 11 and the second supply cell-side anode 21; and a membrane-less electrolysis unit E3, which is provided in the electrolytic cell 30 and performs membrane-less electrolysis of the third aqueous solution L3 to produce hypochlorous acid by passing a third current between the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32.

[0142] With the above configuration, by passing the first current, chloride ions contained in the first aqueous solution L1 stored in the first supply tank 10 permeate through the anion exchange membrane 41 and are supplied to the third aqueous solution L3 stored in the electrolytic bath 30. Furthermore, by passing the second current, chloride ions contained in the first aqueous solution L1 stored in the first supply tank 10 permeate through the anion exchange membrane 41 and are supplied to the third aqueous solution L3 stored in the electrolytic bath 30. Therefore, it is possible to provide the space purification device 1 that can stably generate hypochlorous acid gas for a long period of time without externally supplying an aqueous solution containing chloride ions.

[0143] The space purification device 1 according to this embodiment includes a current control unit 50 that controls the first electrolysis with a diaphragm, the second electrolysis with a diaphragm, and the electrolysis without a diaphragm. The current control unit 50 applies the first current, the second current, and the third current at predetermined ratios so that the hypochlorous acid concentration in the third aqueous solution L3 is maintained at a predetermined concentration.

[0144] With the above configuration, the concentration of hypochlorous acid in the third aqueous solution L3 can be maintained at a predetermined concentration, thereby providing the space purification device 1 that can stably generate a desired amount of hypochlorous acid gas.

[0145] In the space purification device 1 according to this embodiment, the current control unit 50 applies a first current to replenish the chloride ions contained in the third aqueous solution L3 that have been reduced by the diaphragm-less electrolysis, thereby causing chloride ions contained in the first aqueous solution L1 stored in the first supply tank 10 to pass through the anion exchange membrane 41 and be supplied to the third aqueous solution L3. In addition, the current control unit 50 applies a second current to replenish the metal ions contained in the third aqueous solution L3 that have been reduced by the purification operation, thereby causing metal ions contained in the second aqueous solution L2 stored in the second supply tank 20 to pass through the cation exchange membrane 42 and be supplied to the third aqueous solution L3, and causing chloride ions contained in the first aqueous solution L1 stored in the first supply tank 10 to pass through the anion exchange membrane 41 and be supplied to the third aqueous solution L3.

[0146] With the above configuration, the current control unit 50 (1) controls the first current so as to replenish chloride ions contained in the third aqueous solution L3 that have been reduced by diaphragm-less electrolysis in the diaphragm-less electrolysis unit E3. This allows chloride ions contained in the first aqueous solution L1 to pass through the anion exchange membrane 41 and be supplied to the third aqueous solution L3. Furthermore, when the third aqueous solution L3 is a sodium chloride aqueous solution, the current control unit 50 (2) controls the second current of the second diaphragm-containing electrolysis unit E2a so as to replenish chloride ions and sodium ions contained in the third aqueous solution L3 that have been reduced by salt splashing. This allows chloride ions contained in the first aqueous solution L1 to pass through the anion exchange membrane 41 and be supplied to the third aqueous solution L3, and sodium ions contained in the second aqueous solution L2 to be supplied to the third aqueous solution L3. Furthermore, when the second diaphragm-containing electrolysis unit E2a is used, more chloride ions can be supplied to the electrolytic cell 30 than when the second diaphragm-containing electrolysis unit E2b is used. Furthermore, compared to the case where the second membrane electrolysis section E2b of the second example is used, the increase in hydrogen ions in the third aqueous solution L3 that accompanies an increase in the current ratio of the first current (an increase in the amount of current) can be suppressed, and the decrease in pH in the third aqueous solution L3 can be suppressed.

[0147] In the space purification device 1 according to the present embodiment, as a second example, the first supply tank 10 includes a first supply tank-side cathode 11, the second supply tank 20 includes a second supply tank-side anode 21, and the electrolytic cell 30 includes an electrolytic cell-side anode 31 and an electrolytic cell-side cathode 32. The electrolysis system also includes a first membrane-with-diaphragm electrolysis unit E1, which is provided across the electrolytic cell 30 and the first supply cell 10 and performs first membrane-with-diaphragm electrolysis via the anion exchange membrane 41 by passing a first current between the electrolytic cell-side anode 31 and the first supply cell-side cathode 11; a second membrane-with-diaphragm electrolysis unit E2b, which is provided across the electrolytic cell 30 and the second supply cell 20 and performs second membrane-with-diaphragm electrolysis via the cation exchange membrane 42 by passing a second current between the electrolytic cell-side cathode 32 and the second supply cell-side anode 21; and a membrane-less electrolysis unit E3, which is provided in the electrolytic cell 30 and performs membrane-less electrolysis of the first aqueous solution L1 to produce hypochlorous acid by passing a third current between the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32.

[0148] With the above configuration, by passing the first current, chloride ions contained in the first aqueous solution L1 stored in the first supply tank 10 permeate through the anion exchange membrane 41 and are supplied to the third aqueous solution L3 stored in the electrolytic tank 30. Therefore, it is possible to provide the space purification device 1 that can stably generate hypochlorous acid gas for a long period of time without supplying an aqueous solution containing chloride ions from the outside.

[0149] The space purification device 1 according to this embodiment includes a current control unit 50 that controls the first electrolysis with a diaphragm, the second electrolysis with a diaphragm, and the electrolysis without a diaphragm. The current control unit 50 applies the first current, the second current, and the third current at predetermined ratios so that the hypochlorous acid concentration in the third aqueous solution L3 is maintained at a predetermined concentration.

[0150] With the above configuration, the concentration of hypochlorous acid in the third aqueous solution L3 can be maintained at a predetermined concentration, thereby providing the space purification device 1 that can stably generate a desired amount of hypochlorous acid gas.

[0151] In the space purification device 1 according to this embodiment, the current control unit 50 applies a first current to replenish the chloride ions contained in the third aqueous solution L3 that have been reduced by the diaphragm-less electrolysis, thereby causing the chloride ions contained in the first aqueous solution L1 stored in the first supply tank 10 to pass through the anion exchange membrane 41 and be supplied to the third aqueous solution L3. In addition, the current control unit 50 applies a second current to replenish the metal ions contained in the third aqueous solution L3 that have been reduced by the purification operation, thereby causing the metal ions contained in the second aqueous solution L2 stored in the second supply tank 20 to pass through the cation exchange membrane 42 and be supplied to the third aqueous solution L3.

[0152] With the above configuration, the current control unit 50 (1) controls the first current so as to replenish chloride ions contained in the third aqueous solution L3 that have been reduced by the diaphragm-less electrolysis in the diaphragm-less electrolysis unit E3. This allows chloride ions contained in the first aqueous solution L1 to pass through the anion exchange membrane 41 and be supplied to the third aqueous solution L3. Furthermore, when the third aqueous solution L3 is a sodium chloride aqueous solution, the current control unit 50 (2) controls the second current of the second diaphragm-containing electrolysis unit E2a so as to replenish chloride ions and sodium ions contained in the third aqueous solution L3 that have been reduced by salt splashing. This allows sodium ions contained in the second aqueous solution L2 to be supplied to the third aqueous solution L3. Furthermore, when the second diaphragm-containing electrolysis unit E2b is used, the amount of current flowing through the electrolytic cell-side cathode 32 is increased by increasing the current rate of the second current so as to correspond to the increase in the current rate of the first current, and hydroxide ions (OH － Therefore, it is possible to suppress a decrease in pH of the third aqueous solution L3 due to an increase in hydrogen ions.

[0153] The second aqueous solution L2 used in the space purification device 1 according to this embodiment is an aqueous solution containing metal ions, and is at least one aqueous solution selected from the group consisting of disodium hydrogen phosphate aqueous solution, sodium bicarbonate aqueous solution, lithium carbonate aqueous solution, and potassium carbonate aqueous solution.

[0154] By providing the above configuration, the hypochlorous acid concentration of the third aqueous solution L3 can be maintained at a predetermined concentration. Therefore, it is possible to provide an air purification device 1 that can stably generate a desired amount of hypochlorous acid gas. Furthermore, when a disodium hydrogen phosphate aqueous solution or a sodium bicarbonate aqueous solution is used as the second aqueous solution L2, the GHS classification of these solutions is similar to that of sodium chloride, making it possible to provide an air purification device 1 with improved safety.

[0155] In the space purification device 1 according to this embodiment, the air supplied to the electrolytic cell 30 is released as bubbles B into the third aqueous solution L3, the released bubbles B are mixed with hypochlorous acid, and the resulting mixed air M is released into the external space R.

[0156] With the above configuration, gas-liquid contact occurs between the bubbles B generated by bubbling and the third aqueous solution L3. The gas-liquid contact that generates the bubbles B in the third aqueous solution L3 by bubbling can incorporate more hypochlorous acid into the bubbles B than gas-liquid contact between air and the liquid surface S3 of the third aqueous solution L3. Therefore, the mixed air M that incorporates more hypochlorous acid can be released into the external space R.

[0157] The present disclosure is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present disclosure.

[0158] An outline of one aspect of the present disclosure is as follows.

[0159] (Item 1) A space purification device comprising: a first supply tank that stores a first aqueous solution containing chloride ions, and that performs first membrane-with-diaphragm electrolysis to cause the chloride ions contained in the first aqueous solution to permeate through an anion exchange membrane and supply them to a third aqueous solution; a second supply tank that stores a second aqueous solution containing at least one metal ion selected from the group consisting of sodium ions, lithium ions, and potassium ions, and that performs second membrane-with-diaphragm electrolysis to cause the metal ions selected from the group contained in the second aqueous solution to permeate through a cation exchange membrane and supply them to the third aqueous solution; and an electrolytic cell that stores the third aqueous solution containing chloride ions and produces hypochlorous acid by membrane-less electrolysis of the third aqueous solution, wherein a purification operation is performed in which air introduced from an external space flows through the electrolytic cell and is released into the external space together with the hypochlorous acid.

[0160] (Item 2) The space purification device according to Item 1, wherein the first supply tank includes a first supply tank-side cathode, the second supply tank includes a second supply tank-side anode, the electrolytic cell includes an electrolytic cell-side anode and an electrolytic cell-side cathode, a first diaphragm-containing electrolysis section provided between the electrolytic cell and the first supply tank, and configured to perform the first diaphragm-containing electrolysis via the anion exchange membrane by passing a first current between the electrolytic cell-side anode and the first supply tank-side cathode, a second diaphragm-containing electrolysis section provided between the first supply tank and the second supply tank, and configured to perform the second diaphragm-containing electrolysis via the anion exchange membrane and the cation exchange membrane by passing a second current between the first supply tank-side cathode and the second supply tank-side anode, and a diaphragm-less electrolysis section provided in the electrolytic cell, and configured to perform the diaphragm-less electrolysis of the third aqueous solution to produce hypochlorous acid by passing a third current between the electrolytic cell-side anode and the electrolytic cell-side cathode.

[0161] (Item 3) The space purification device according to Item 2, further comprising a current control unit that controls the first electrolysis with a diaphragm, the second electrolysis with a diaphragm, and the electrolysis without a diaphragm, wherein the current control unit applies the first current, the second current, and the third current at predetermined ratios so that the hypochlorous acid concentration in the third aqueous solution is maintained at a predetermined concentration.

[0162] (Item 4) The space purification device according to Item 3, wherein the current control unit applies the first current so as to replenish chloride ions contained in the third aqueous solution that have been reduced by the membraneless electrolysis, thereby causing chloride ions contained in the first aqueous solution stored in the first supply tank to pass through the anion exchange membrane and be supplied to the third aqueous solution; and applies the second current so as to replenish metal ions contained in the third aqueous solution that have been reduced by the purification operation, thereby causing metal ions contained in the second aqueous solution stored in the second supply tank to pass through the cation exchange membrane and be supplied to the third aqueous solution, and causing chloride ions contained in the first aqueous solution stored in the first supply tank to pass through the anion exchange membrane and be supplied to the third aqueous solution.

[0163] (Item 5) The space purification device according to Item 1, wherein the first supply tank includes a first supply tank-side cathode, the second supply tank includes a second supply tank-side anode, the electrolytic tank includes an electrolytic tank-side anode and an electrolytic tank-side cathode, a first diaphragm-containing electrolysis section provided between the electrolytic tank and the first supply tank, performing the first diaphragm-containing electrolysis via the anion exchange membrane by passing a first current between the electrolytic tank-side anode and the first supply tank-side cathode, a second diaphragm-containing electrolysis section provided between the electrolytic tank and the second supply tank, performing the second diaphragm-containing electrolysis via the cation exchange membrane by passing a second current between the electrolytic tank-side cathode and the second supply tank-side anode, and a diaphragm-less electrolysis section provided in the electrolytic tank, performing the diaphragm-less electrolysis of the first aqueous solution to produce hypochlorous acid by passing a third current between the electrolytic tank-side anode and the electrolytic tank-side cathode.

[0164] (Item 6) The space purification device according to Item 5, further comprising a current control unit that controls the first electrolysis with a diaphragm, the second electrolysis with a diaphragm, and the electrolysis without a diaphragm, wherein the current control unit applies the first current, the second current, and the third current at predetermined ratios so that the hypochlorous acid concentration in the third aqueous solution is maintained at a predetermined concentration.

[0165] (Item 7) The space purification device according to Item 6, wherein the current control unit supplies chloride ions contained in the first aqueous solution stored in the first supply tank through the anion exchange membrane to the third aqueous solution by passing the first current so as to replenish chloride ions contained in the third aqueous solution that have been reduced by the membraneless electrolysis, and supplies metal ions contained in the second aqueous solution stored in the second supply tank through the cation exchange membrane to the third aqueous solution by passing the second current so as to replenish metal ions contained in the third aqueous solution that have been reduced by the purification operation.

[0166] (Item 8) The space purification device according to Item 1, Item 2, or Item 5, wherein the aqueous solution containing metal ions is at least one aqueous solution selected from the group consisting of a disodium hydrogen phosphate aqueous solution, a sodium bicarbonate aqueous solution, a lithium carbonate aqueous solution, and a potassium carbonate aqueous solution.

[0167] (Item 9) The space purification device according to Item 1, Item 2, or Item 5, wherein the air supplied to the electrolytic cell is released as bubbles into the third aqueous solution, the released bubbles are mixed with the hypochlorous acid, and the resulting mixed air is released into the external space.

[0168] (Item 10) The space purification device according to Item 1, wherein the first supply tank side cathode and the electrolytic cell side anode are arranged opposite each other with the anion exchange membrane interposed therebetween, the electrolytic cell side anode and the electrolytic cell side cathode are arranged opposite each other, the electrolytic cell side cathode and the second supply tank side anode are arranged opposite each other with the cation exchange membrane interposed therebetween, and the first supply tank side cathode, the anion exchange membrane, the electrolytic cell side anode, the electrolytic cell side cathode, the cation exchange membrane, and the second supply tank side anode are arranged at a predetermined interval along one direction.

[0169] 1. Space purification device 10. 1st supply tank 11. 1st supply tank-side cathode 12. 1st supply tank-side internal space 13. 1st discharge port 20. 2nd supply tank 21. 2nd supply tank-side anode 22. 2nd supply tank-side internal space 23. 2nd discharge port 30. Electrolytic cell 31. Electrolytic cell-side anode 32. Electrolytic cell-side cathode 33. Air supply unit 34. Air supply duct 35. Electrolytic cell-side internal space 36. Water recovery unit 37. Discharge port 38. Water level detection unit 41. Anion exchange membrane 42. Anode exchange membrane 50. Current control unit 50a. Voltage acquisition unit 50b. Calculation unit 50c. Estimation unit 51. Wiring 52. Wiring 53. Wiring 54. Wiring A. Air flow path B. Bubble C. Housing E1. 1st diaphragm electrolysis unit E2. 2nd diaphragm electrolysis unit E2a. Second electrolysis section with diaphragm E2b Second electrolysis section with diaphragm E3 Electrolysis section without diaphragm L1 First aqueous solution L2 Second aqueous solution L3 Third aqueous solution M Mixed air R External space S1 Liquid level S2 Liquid level S3 Liquid level

Claims

1. A space purification device comprising: a first supply tank for storing a first aqueous solution containing chloride ions, and for supplying the chloride ions contained in the first aqueous solution to a third aqueous solution by passing them through an anion exchange membrane through a first diaphragm-equipped electrolysis; a second supply tank for storing a second aqueous solution containing at least one metal ion selected from the group consisting of sodium ions, lithium ions, and potassium ions, and for supplying the metal ions selected from the group contained in the second aqueous solution to a cation exchange membrane through a second diaphragm-equipped electrolysis, and for supplying the metal ions to the third aqueous solution by passing them through an ion exchange membrane through a second diaphragm-equipped electrolysis; and an electrolytic cell for storing the third aqueous solution containing chloride ions and for producing hypochlorous acid by electrolyzing the third aqueous solution without a diaphragm, wherein a purification operation is performed in which air introduced from an external space flows through the electrolytic cell and is released into the external space together with the hypochlorous acid.

2. The space purification device according to claim 1, wherein the first supply tank is equipped with a first supply tank-side cathode, the second supply tank is equipped with a second supply tank-side anode, the electrolytic tank is equipped with an electrolytic tank-side anode and an electrolytic tank-side cathode, a first diaphragm-equipped electrolysis section provided between the electrolytic tank and the first supply tank, which performs the first diaphragm-equipped electrolysis via the anion exchange membrane by passing a first current between the electrolytic tank-side anode and the first supply tank-side cathode, a second diaphragm-equipped electrolysis section provided between the first supply tank and the second supply tank, which performs the second diaphragm-equipped electrolysis via the anion exchange membrane and the cation exchange membrane by passing a second current between the first supply tank-side cathode and the second supply tank-side anode, and a diaphragm-less electrolysis section provided in the electrolytic tank, which performs the diaphragm-less electrolysis of the third aqueous solution to produce hypochlorous acid by passing a third current between the electrolytic tank-side anode and the electrolytic tank-side cathode.

3. The space purification device according to claim 2, further comprising a current control unit that controls the first electrolysis with a diaphragm, the second electrolysis with a diaphragm, and the electrolysis without a diaphragm, and the current control unit applies the first current, the second current, and the third current at a predetermined ratio so that the hypochlorous acid concentration in the third aqueous solution is maintained at a predetermined concentration.

4. The space purification device described in claim 3, wherein the current control unit applies the first current so as to replenish the chloride ions contained in the third aqueous solution that have been reduced by the membraneless electrolysis, thereby causing the chloride ions contained in the first aqueous solution stored in the first supply tank to pass through the anion exchange membrane and be supplied to the third aqueous solution, and applies the second current so as to replenish the metal ions contained in the third aqueous solution that have been reduced by the purification operation, thereby causing the metal ions contained in the second aqueous solution stored in the second supply tank to pass through the cation exchange membrane and be supplied to the third aqueous solution, and causing the chloride ions contained in the first aqueous solution stored in the first supply tank to pass through the anion exchange membrane and be supplied to the third aqueous solution.

5. The space purification device according to claim 1, wherein the first supply tank is equipped with a first supply tank-side cathode, the second supply tank is equipped with a second supply tank-side anode, the electrolytic tank is equipped with an electrolytic tank-side anode and an electrolytic tank-side cathode, a first diaphragm-equipped electrolysis section provided between the electrolytic tank and the first supply tank, which performs the first diaphragm-equipped electrolysis via the anion exchange membrane by passing a first current between the electrolytic tank-side anode and the first supply tank-side cathode, a second diaphragm-equipped electrolysis section provided between the electrolytic tank and the second supply tank, which performs the second diaphragm-equipped electrolysis via the cation exchange membrane by passing a second current between the electrolytic tank-side cathode and the second supply tank-side anode, and a diaphragm-less electrolysis section provided in the electrolytic tank, which performs the diaphragm-less electrolysis of the first aqueous solution to produce hypochlorous acid by passing a third current between the electrolytic tank-side anode and the electrolytic tank-side cathode.

6. The space purification device according to claim 5, further comprising a current control unit that controls the first electrolysis with a diaphragm, the second electrolysis with a diaphragm, and the electrolysis without a diaphragm, and the current control unit applies the first current, the second current, and the third current at a predetermined ratio so that the hypochlorous acid concentration in the third aqueous solution is maintained at a predetermined concentration.

7. The space purification device described in claim 6, wherein the current control unit supplies chloride ions contained in the first aqueous solution stored in the first supply tank through the anion exchange membrane to the third aqueous solution by passing the first current so as to replenish chloride ions contained in the third aqueous solution that have been reduced by the membraneless electrolysis, and supplies metal ions contained in the second aqueous solution stored in the second supply tank through the cation exchange membrane to the third aqueous solution by passing the second current so as to replenish metal ions contained in the third aqueous solution that have been reduced by the purification operation.

8. The space purification device according to claim 1, claim 2 or claim 5, wherein the aqueous solution containing metal ions is at least one aqueous solution selected from the group consisting of disodium hydrogen phosphate aqueous solution, sodium hydrogen carbonate aqueous solution, lithium carbonate aqueous solution and potassium carbonate aqueous solution.

9. The space purification device according to claim 1, claim 2 or claim 5, wherein the air supplied to the electrolytic cell is released as bubbles into the third aqueous solution, the released bubbles are mixed with the hypochlorous acid, and the resulting mixed air is released into the external space.

10. The space purification device according to claim 1, wherein the first supply tank side cathode and the electrolytic cell side anode are arranged opposite each other with the anion exchange membrane interposed therebetween, the electrolytic cell side anode and the electrolytic cell side cathode are arranged opposite each other, the electrolytic cell side cathode and the second supply tank side anode are arranged opposite each other with the cation exchange membrane interposed therebetween, and the first supply tank side cathode, the anion exchange membrane, the electrolytic cell side anode, the electrolytic cell side cathode, the cation exchange membrane, and the second supply tank side anode are arranged at a predetermined interval along one direction.

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